Background
Much of the research literature about the use of family planning generalizes contraceptive use among all women, using age as a covariate. In Uganda, a country with divergent trends in modern family planning use, this study was set to explore whether or not the predictors of contraceptive use differ by age. This was assessed by using data from the 2011 Uganda Demographic and Health Survey (UDHS).

Methods
We restricted the sample from each round to fecund, non-pregnant married women age 15–34 who were sexually active within one year prior to the survey, resulting in a sample of 2,814 women. We used logistic regression with age variable used as an interaction term to model the relationship between selected independent variables and the outcome variable (modern contraception use) for each group of women.

Results
We found that the key factors associated with use of modern contraceptives varied among young and older married women age 15–24 and 25–34 respectively. Results showed that perception on distance to health facility, listening to radio and geographical differences exhibited significant variability in contraceptive use among the young and the older women. Other key factors that were important for both age groups in explaining contraceptive use were; desire to have children after two years and education level.

Conclusions
Addressing contraceptive use among old and young women in Uganda requires concerted efforts that target such women to address the socio economic barriers that exist. There is need for increased access of family planning service to the population through strengthening the use of Village Health Teams (VHTs) whose service is currently limited in coverage (MoH, 2009). Given the variation in contraceptive use between the two age groups, our findings further suggest that there is need for variability in media targeting among the young and the older women categories for improved use of modern contraceptives, for instance using alternative media strategies to reach the young women. Family planning policies should also be tailored to address the specific needs of different age groups of women with varied geographical locations.