Background As the evidence continues to emerge about the relationship between sudden unexpected death in infancy (SUDI) and the way an infant sleeps, providing consistent and evidence-informed recommendations on how best to sleep infants is an ongoing challenge. A recent case series study in the state of Victoria, Australia, identified 45.8% of sleep-related infant deaths occurred whilst bed-sharing. This study prompted the need for further exploration of infant sleeping practices, including bed-sharing, in this population. Methods A cross-sectional survey of 2745 mothers attending the Maternal and Child Health (MCH) Service across Victoria, Australia was conducted. Data included the prevalence and circumstances of bed-sharing, family demographics, and SUDI risk and protective factors. Associations between bed-sharing and SUDI risk and protective factors were examined using univariate and multivariate analyses. Results Bed-sharing prevalence was found to be 44.7%, with 21.5% reporting that this was intended. Multivariate analyses showed bed-sharing was less likely amongst those with an annual household income above $AUS104, 000 (OR 0.72; 95% CI 0.54-0.96) and more likely amongst mothers who breastfed (OR 1.71; 95% CI 1.23-2.37). Conclusions Bed-sharing prevalence in this population compares closely with the Victorian case series study and a previous cross-sectional study in the state of Queensland, Australia, in 2002. Noted gaps in how families are implementing current recommendations about reducing the risk of SUDI were identified for sleep position, sleep location and the sleep environment. Further consideration needs to be given to addressing these gaps and applying these findings of current bed-sharing practices to the development of infant safe sleeping policy and programs.