Purpose – The purpose of this paper is to investigate the relationship between child sexual abuse and sexual risk behaviours as well as its potential mediators. Design/methodology/approach – This cross-sectional study used data from a cross-sectional study from 12,800 women between 15 and 49 years of age included in the 2008 Nigerian Demographic and Health Survey. Structural equation modelling (SEM) was applied to assess the association between childhood sexual abuse (CSA) and sexual risk behaviours. Findings – The authors found that CSA was directly associated with sexual risk behaviours. In addition, the association between CSA and sexual risk behaviour was also partially mediated by alcohol and cigarette use. Research limitations/implications – The results show that being abused in childhood is important for the subsequent development of sexual risk behaviours in adulthood and the association is mediated by alcohol and cigarette use. Practical implications – The results may be helpful for policy makers and health care planners in designing cultural sensitive public health intervention that will reduce the burden of CSA, its long-term effects (sexual risk behaviours) and intervening mediators that increase the risks. Social implications – These findings suggest that to reduce sexual risks, interventions to address sexual abuse needs to include other social problems (smoking, alcohol) that victims result to when faced with trauma. Originality/value – The current study is the only one so far in sub-Saharan Africa to have explored the relation between CSA and sexual risk behaviours using SEM.