This study investigates inequalities at the province level of the use of modern contraception and the proportion of short birth intervals among women in the DRC using data from the 2007 Demographic and Health Survey. Logistic regression and Bayesian geo-additive models were used. The posterior odds ratio and the associated 95% credible interval (95% CI) were estimated using Markov Chain Monte Carlo (MCMC) techniques. Posterior spatial effects were mapped at the province level with the associated posterior probability maps showing statistical significance at 5%. The overall rates of modern contraception use among the entire sample of women (15-49 years old; N = 7172) and youth (15-24 years old; N = 1389) were 5.7% and 6.0% respectively. However, there was striking variation in contraceptive use between the two groups across provinces with a clear east-to-west gradient. The highest use in the total sample was in Nord-Kivu (OR 1.32; 95% CI 1.12, 1.55) and Bas Congo provinces (1.47; 1.22, 1.78). For the youth, the highest use was observed in Nord-Kivu (1.19; 0.92, 1.65). In multivariate Bayesian geo-additive regression analyses among the entire sample of women, factors consistently associated with lower use of modern contraception were living in rural areas (0.71; 0.62, 0.82), living in low-income households (0.67; 0.54, 0.80) and having no education (0.83; 0.67, 0.97). For the youth sample, living in low-income households (0.57; 0.41, 0.84) and no breast-feeding (0.64; 0.47, 0.86) were consistently associated with a lower use of modern contraception. The study shows a distinct geographic pattern in the use of modern contraception in youth and the entire sample of women in the DRC, suggesting a potential role for socioeconomic factors, such as accessibility, affordability and availability, as well as environmental factors at the province level beyond individual-level risk factors.