The Canadian population is aging as the children of the "baby boom" move into and through middle age and then on toward the retirement years. The "baby bust" that followed the boom has slowed the rate of population growth and reduced sharply the supply of young people entering the labour force. The rates of participation of women in the labour force are now approaching those of men and little can be expected in the way of continuing further growth from that source. Immigration has thus taken on an important role in determining the rates of population and labour force growth. We explore these and related issues and draw out their implications for Canada's economic growth prospects.