Increasing longevity and  falling fertility have increased interest in financing retirement age and have increased the burden of old age in an ageing society. This research is based on data from 41 countries of OECD and BRICS, between 1995 and 2017. By employing the fixed-effect estimation method, this study is to test and compare the relationship between the child and old-age dependency ratios, life expectancy and savings rate of these countries. The two groups of countries represent developed (OECD) and emerging (BRICS) countries with different level of development and states of ageing. The estimation results show that the savings rate of OECD countries can be explained by the old-age and child dependency ratios and life expectancy, but life expectancy has a greater impact on the savings rate. However, although the savings rate in BRICS countries is also positively affected by life expectancy, the impact of child dependency ratio is much greater than life expectancy. But, the effect of old-age dependency ratios on savings is insignificant in BRICS countries.