Background Intimate partner violence (IPV) is a global public health and human rights concern, though there is limited evidence on how to prevent it. This secondary analysis of data from the SASA! Study assesses the potential of a community mobilisation IPV prevention intervention to reduce overall prevalence of IPV, new onset of abuse (primary prevention) and continuation of prior abuse (secondary prevention).

Methods A pair-matched cluster randomised controlled trial was conducted in 8 communities (4 intervention, 4 control) in Kampala, Uganda (2007–2012). Cross-sectional surveys of community members, 18–49 years old, were undertaken at baseline (n=1583) and 4 years postintervention implementation (n=2532). Outcomes relate to women's past year experiences of physical and sexual IPV, emotional aggression, controlling behaviours and fear of partner. An adjusted cluster-level intention-to-treat analysis compared outcomes in intervention and control communities at follow-up.

Results At follow-up, all types of IPV (including severe forms of each) were lower in intervention communities compared with control communities. SASA! was associated with lower onset of abuse and lower continuation of prior abuse. Statistically significant effects were observed for continued physical IPV (adjusted risk ratio 0.42, 95% CI 0.18 to 0.96); continued sexual IPV (0.68, 0.53 to 0.87); continued emotional aggression (0.68, 0.52 to 0.89); continued fear of partner (0.67, 0.51 to 0.89); and new onset of controlling behaviours (0.38, 0.23 to 0.62).

Conclusions Community mobilisation is an effective means for both primary and secondary prevention of IPV. Further support should be given to the replication and scale up of SASA! and other similar interventions.