Over 65s to increase by 63 per cent by 2035.
New figures from Scotland's Registrar General anticipate an increase of 63 per cent in the number of people aged 65 or over by 2035.
The forecast comes as Census data reveals that Scotland's population reached 5,254,800 in mid-2011 - the highest level ever recorded.
Registrar General George MacKenzie said: "Behind this headline figure, the pattern of population change is more complex. The population in some areas of Scotland has decreased. Although births still outnumber deaths, there were fewer births than in 2010. In 2011, the number of deaths in Scotland dropped to 53,661, the lowest annual total since registration began in 1855."
Life expectancy in Scotland has improved greatly over the last 25 years, increasing from 69.1 years for men and 75.3 years for women born around 1981, to 76.1 years for men and 80.6 years for women born around 2010.
Despite recent improvements, Scottish men and women have poor life expectancy compared with most of the EU - 3.6 years lower for men and 4.7 years lower for women compared with the countries where life expectancy is highest. Death rates from cancer, coronary heart disease and stroke in Scotland remain well above the rates for the other countries in the UK.
Age Scotland spokesperson Doug Anthoney said: "That Scotland's population is ageing is cause for celebration, not alarm. Older people play an invaluable role in Scottish society; as workers, volunteers, carers and cultural contributors.
"Concerted and sustained action will be needed to bring life expectancy in Scotland more in line its neighbour, however possibly the bigger challenge is to make sure that healthy life expectancy rises more swiftly. For this to happen we will need to see more investment in preventative services that enable older people to enjoy independence, health and wellbeing in their homes; from the local lunch club to the community bus that takes them there."