The High Court in Glasgow heard Brian Docherty's car crashed into friends Elizabeth McGuiness and Barbara McCready as they walked from a church in Motherwell, North Lanarkshire, in June last year.
Miss McGuiness died and Mrs McCready was left seriously injured.
Docherty, from Uddingston, South Lanarkshire, should have told the DVLA of his diabetic condition and should not have been on the road.
The 45-year-old also had a poor history of taking medication to control his diabetes.
Jailing him, judge Lady Stacey said: "Nothing I can say or indeed anything you can say or do can lessen the grief for the family of Miss McGuiness.
"You will have to live with the knowledge of causing the death of one woman and serious injury to another. You knew of your condition and failed to take the steps you should have taken which would have led to the surrender of your licence.
"You knew you were at risk of hypoglycemic attacks. You had suffered from such in the past and had suffered from one before the accident."
Docherty admitted causing the death of Miss McGuiness by dangerous driving and leaving Mrs McCready severely injured.
Miss McGuiness, 63, and Mrs McCready, 64, had been at Motherwell Cathedral and were walking along the pavement when they were knocked down.
The court was shown CCTV footage of the crash.
Prosecutor Murdo MacTaggart said: "A witness saw that the accused appeared to be having some kind of fit and that his whole body was shaking."
Docherty accelerated, forcing other drivers to dodge him. He then careered into a parked car before mounting the pavement and hitting the two women.
Miss McGuiness was dragged under the wheels of Docherty's car. Mrs McCready was thrown into the air.
Docherty's car came to a halt after smashing into railings.
Miss McGuiness, who latterly worked as a support worker for North Lanarkshire Council, was pronounced dead at the scene having suffered extensive head and leg injuries. Mrs McCready was taken to hospital with multiple fractures.
Mr MacTaggart told the court: "It appears the accused suffered a hypoglycemic attack while he was driving.
"His low blood-sugar level would have severely affected his ability to drive and he would have been close to passing out at the time of the incident."
Medical records showed Docherty, who had been forced to give up his job as a driver, poorly controlled his diabetes.
Mr MacTaggart added: "He had suffered a number of hypoglycemic attacks in the past. He had attended his GP 12 days before this incident and complained he had suffered an attack during the night."
The court was told how Mrs McCready, a retired school cook, was in hospital for three months. She still has difficulty walking and is fearful of being anywhere near traffic.
Solicitor advocate Ali Murray, defending, said: "Mr Docherty has expressed remorse for what he did. He accepts full responsibility for this."
On top of the jail sentence, Docherty was also banned from driving for 10 years.