Robert Palmer, 32, mowed down Andrew McMenigall, 47, and Toby Wallace, 36, who died almost instantly in the crash on the A30 in Newquay, Cornwall, on July 2 last year.
The pair, who worked for Aberdeen Asset Management (AAM), were 40 miles (64km) into the 960-mile (1,545km) bike ride to raise money for two charities when they were struck by Palmer's white Renault lorry.
At an earlier hearing at Truro Crown Court, Palmer, of Grimscott, Bude, Cornwall, pleaded guilty to two charges of causing death by dangerous driving.
He also admitted a further charge of dangerous driving in relation to a second similar crash weeks later on the A30 near Okehampton.
At the time of the crash Palmer - a night time delivery driver for Frys Logistics Ltd in Launceston - had little sleep because instead of resting during the day he was working on vehicle maintenance for the firm.
He was also habitually using his iPhone to send text messages while carrying out deliveries for discount store Lidl between Cornwall and Weston-super-Mare, the court heard.
Jailing the father-of-one, Judge Christopher Harvey Clark QC said: "The evidence is at the time when this accident occurred you had almost certainly fallen asleep but it is equally clear you were disregarding the rules of the road by texting continuously and it would seem at length.
"You completely ignored their presence on the road. In the words of prosecutor Mr Lee you mowed them down.
"It is clear that at the time when this tragic accident occurred you were suffering from extreme fatigue and exhaustion.
"You should not have been driving at all at that time. You failed to ensure that you took sufficient rests. People should not drive when they are feeling very sleepy or as you were totally exhausted.
"All the indications are that long before the fatal collision you must or should have been aware of your condition.
"It is also clear - although I accept not a primary cause of the accident - you had been inappropriately and illegally using your mobile telephone.
"You were using it habitually. People who use a handheld mobile telephone and text while driving carry a terrible risk to other road users.
"The reason's perfectly obvious - a driver's attention to the road is disturbed by his or her texting."
Palmer was also banned from driving for 10 years and ordered to take an extended driving test.
The judge said both Mr McMenigall and Mr Wallace were "fine and good men" who were very successful in both their careers and personal lives.
"Both men were experienced and safe cyclists. It is clear at the relevant time they were visible to other road users," the judge told Palmer.
"Both men wanted to raise money for a truly worthy cause. They were the kind of people who make this world a better place for the rest of us.
"They met their deaths as a result of your criminal actions. I recognise the terrible loss to their families and friends. They cannot be replaced.
"It has to be said that no sentence I pass upon you can make up in any way, shape or form for the loss suffered to their families.
"All I can do is sentence you according to the law. In this country we do not have sentencing based on the old principle of an eye for an eye or a tooth for a tooth."
The judge added: "Your driving involved a deliberate decision to ignore or a flagrant disregard for the rules of the road and an apparent disregard for the danger caused to others."
Mr McMenigall lived in Edinburgh with his wife Anne and their two children, Jennifer, aged 15, and 12-year-old Lucy.
He was a keen triathlete and had previously served as an officer in the Army before joining AAM.
Mr Wallace, who was married to Claire, lived in Philadelphia where he worked for AAM.
He was born in the UK, went to school in Southampton and studied at Cambridge University before working in London, Sydney and the US. Mr Wallace had twice rowed for Cambridge in the Boat Race, the court heard.
He was also part of an eight-man team who rowed across the Atlantic to raise money for charity.
Their bike ride was to raise money for the Kirsten Scott Memorial Trust, named after a 25-year-old colleague who died from cancer in 2011.
Mr McMenigall was also raising money for It's Good 2 Give, an Edinburgh-based charity that offers support to people with cancer and their families.
One of his daughters had been diagnosed with, and recovered from, a brain tumour.
The pair were hoping to raise £10,000 for the two charities. Donations have now exceeded that more than five-fold.
Prosecutor Philip Lee told the court how the fatal crash happened at 8.30am as Palmer returned to his depot in his white articulated Renault lorry.
The experienced lorry driver had left Cornwall the previous evening to pick up goods for Lidl at its depot in Weston-super-Mare and had driven overnight to deliver them to Penzance and Hayle.
Other motorists had seen Mr McMenigall and Mr Wallace cycling along the road in single file wearing reflective clothing.
Drivers had also noticed Palmer's erratic driving on the 50mph A30 and he weaved across the dual carriageway and ran over the rumble strips alongside the hard shoulder.
One car driver had overtaken Palmer's lorry and moved over to the other lane to give the cyclists room as he passed them.
Mr Lee said: "The lorry had not moved out of the inside lane at all and stuck very close to the rumble strips.
"In his rear mirror he basically saw the lorry mow both of the cyclists down."
The prosecutor said that when the collision happened another motorist, who was behind Palmer, did not see him apply his brakes or take any evasive action.
Police investigations found that at the time of the crash Palmer was travelling at 56mph but had previously been doing 62mph in a 40mph zone.
"It is apparent he was habitually driving as fast as the vehicle's speed limiter would allow him," Mr Lee said.
After the crash, Palmer told police that having finished an identical shift the previous day he had gone home and slept up 6.30pm.
But investigations proved this was a lie and he had in fact worked on maintenance at the Frys Logistics depot until 3pm before returning home for a few hours' sleep.
"During the period of 36 hours before the collision on July 2 he had failed to take sufficient rests," Mr Lee said.
Between 5pm on June 30 and 6am on July 1 Palmer had sent over 150 text messages, the court head.
In one text exchange about his lack of sleep, Palmer said: "I've survived so far."
On the morning of July 1, he texted: "Just leaving home, going back to yard."
Later, he texted: "Worked till 3pm had about three hours' kip. Now back on Lidl run."
Mr Lee said: "Far from being home and sleeping, he was going back to work. This defendant was habitually working a day shift in the yard and night time driving shifts.
"He was failing to get enough sleep, of which he was well aware and he continued to do so even after the horrific events of July 2.
"The prosecution observes simply the absence of the phone activity in the period immediately up to the collision as an indication of his fatigue because prior to this collision his phone activity was very persistent."
Palmer also altered his tacograph to cover up for his lack of sleep, Mr Lee said.
The court was also told of another incident weeks later in the early hours of September 20 as Palmer returned from Weston-super-Mare.
As he drove up a steep hill on the A30 in Devon he ploughed into the back of lorry driver Brian Rabey's vehicle.
Mr Rabey was lucky to escape with his life after his vehicle overturned, leaving him with minor injuries.
William Sellick, defending, said Palmer was truly sorry for what he had done and had "blighted the lives of two families".
"He is only too aware of the pain and suffering he has caused and that is something that will remain with him for always," Mr Sellick said.
"It is clear that his remorse is genuine and profound. He is overwhelmed by the enormity of what he has done."
Mr Sellick added that it was unlikely Palmer would ever drive professionally again.
Anne McMenigall and Claire Wallace - the widows of the two cyclists - issued a joint statement after the case.
"There are no words to describe the devastation and loss that we, and both families, feel following the deaths of our husbands. They were exceptional and giant men in every sense of the word," they said.
"It is a tragedy that so many other families are also mourning loved ones who have been killed on Britain's roads, particularly when many of these deaths were completely avoidable.
"So many of these families do not ever see a sentence brought against the person who has killed their husband, their child, their brother, their father.
"UK transport laws are lenient, charges are difficult and onerous to attain, and less and less resource is being dedicated to road traffic collisions.
"Toby and Andrew loved cycling. We believe that the rise in the popularity of the sport must be met by those with the responsibility to improve our transport infrastructure and improve education for drivers.
"We would like to thank everyone who has supported us and been involved in getting us this far."
Sally Moore, from law firm Leigh Day who is representing the families, said: "It seems incredible that this man was ever let behind the wheel of any vehicle, never mind a heavy goods vehicle.
"The judge clearly detailed his criminal behaviour, which resulted in these deaths and astonishingly caused another crash, resulting in injuries to another driver, just 10 weeks after killing Toby and Andrew and whilst on bail for these deaths.
"The circumstances of this second collision were shockingly similar to the fatal collision which killed my clients' husbands.
"Drivers of any vehicle, particularly heavy goods vehicles, carry a significant level of responsibility to other road users.
"The deaths of Toby Wallace and Andrew McMenigall tragically illustrate the catastrophic consequences to cyclists and their families when a criminal lack of respect for other road users replaces that sense of responsibility."