A new report released by the National Records of Scotland showed there were almost 800 more deaths last winter than in the same period the year before.
Mortality during the coldest months is still better than 10 years ago, when more than 21,000 people lost their lives.
However, it has crept up recently, reaching 19,908 between December 2012 and March 2013.
Mortality rates in hospitals also climbed last winter despite medical safety drives.
Beds on wards ran out as the number of patients grew and hundreds of sick people had to wait for more than 12 hours in accident and emergency departments while space was made available.
Professor Jason Leitch, clinical director for the quality unit of NHS Scotland, said: "It appears that last winter, from all the evidence, was a challenging winter and there is a host of reasons around that, some to do with norovirus (the vomiting bug) and respiratory disease."
In addition, he said, consultants on the frontline have described more patients arriving in hospital seriously unwell - possibly reflecting the growing number of elderly people living in Scotland with multiple health problems.
The Herald has run a series of articles highlighting concerns that pressure is growing on the NHS and the campaign, NHS Time for Action, calls for a national review to ensure hospitals and care services are primed to cope with the ageing population.
Professor Leitch said: "We have learned lessons from last winter and the challenges the NHS faced. We have put in place both funding and structural change to prepare the boards for this winter coming."
He also stressed that mortality rates in Scottish hospitals are generally improving. He added: "The overall trend of hospital mortality is down by 12%."
The National Records of Scotland published the figures for the number of deaths registered last winter in Scotland yesterday.
The total of 19,908 is up on 19,119 in 2011-12, 19,626 in 2010-11 and 19,688 in 2009-10. The National Records of Scotland said it is nevertheless the sixth lowest figure logged since records began in 1952.
Its report examines how much mortality rose during last winter compared to the autumn and spring. There were around 2000 more deaths over the winter months. This represents a bigger surge in mortality than Scotland experienced the previous year but is smaller than usual.
Tim Ellis, chief executive of the National Records of Scotland, said: "There are always more deaths in the winter in Scotland than in any other season, but last year had one of the lowest seasonal increases since we started collecting this data in 1951/52. Only three other years have been lower.
"The long-term trend over the last 60 years or so has clearly been downward, although the five-year moving average, which smooths out much of the year-to-year fluctuation, show relatively little change in recent years, at around 2500 'additional' winter deaths.
"There is no single cause of additional deaths in winter. Very few are caused by hypothermia and only a small proportion by influenza. Most are from respiratory and circulatory diseases such as pneumonia, coronary heart disease and stroke."
The Scottish Government has launched an action plan to improve emergency care since last winter, investing £50 million over the next three years.
Of this, £9m has already been given to health boards. The British Medical Association in Scotland has raised concern that the measures taken to date do not go far enough.