Background Exposure to secondhand smoke (SHS) is a significant contributor to ill health in children. A study was undertaken to determine the effectiveness of two brief multi-strategic child health nurse delivered interventions in: decreasing the prevalence of infants exposed to SHS; decreasing the prevalence of smoking amongst parent/carers of infants and increasing the prevalence of household smoking bans. Methods This study was a 3 arm, cluster randomised controlled trial. Clusters were 39 community based well child health clinics in one local area health service. Clinics were stratified according to annual number of client appointments and then randomly assigned in a 1:1:1 ratio, (Intervention 1: Intervention 2: Control), with 13 clinics in each cluster. Parents/carers of infants in the intervention groups received a brief multi-strategic intervention from child health nurses during clinic consultations. Treatment condition 1 included computer delivered risk assessment and feedback and nurse brief advice. Treatment condition 2 included all elements of Treatment condition 1 with the addition of biochemical feedback of infant SHS exposure. Results When compared to the Control group at 12 months, no significant differences in the prevalence of infant exposure to SHS were detected from baseline to follow-up for Treatment condition 1 (OR 1.16, 95 % CI 0.73–1.85, p = 0.53) or Treatment condition 2 (OR 1.30, 95 % CI 0.88–1.92, p = 0.19) Similarly, no significant differences were detected in the proportion of parent/carers who reported that they were smokers (T1:OR 0.95, 95 % CI 0.78–1.15, p = 0.58 and T2:OR 0.97, 95 % CI 0.80–1.18, p = 0.77), or in the proportion of households reported to have a complete smoking ban (T1:OR 1.21, 95 % CI 0.89–1.64, p = 0.23 and T2:OR 1.06, 95 % CI 0.79–1.43, p = 0.68). Conclusions Further research is required to identify effective interventions that can be consistently provided by child health nurses if the potential of such settings to contribute to reductions in child SHS exposure is to be realised.