BackgroundUnhealthy dietary behaviours are one of the key risk factors for many lifestyle-related diseases worldwide. This randomised controlled trial aimed to increase the level of fruit, vegetable and fibre intake and decrease the fat and sugar consumption of mothers with young children (0–5 years) via the playgroup setting.MethodsPlaygroups located in 60 neighbourhoods in Perth, Western Australia were randomly assigned to an intervention (n = 249) or control group (n = 272). Those in the intervention group received a 6-month multi-strategy primarily home-based physical activity and nutrition program (data is only presented on dietary behaviours). Data on dietary consumption was collected via the Fat and Fibre Barometer and frequency of serves of fruit and vegetable and cups of soft drink, flavoured drink and fruit juice. The effects of the intervention on continuous outcome measures were assessed using analysis of variance (ANOVA), after adjusting for mother’s age and the corresponding variables.ResultsThe outcomes of the intervention were positive with the intervention group showing statistically significant improvements, when compared to the control group in the overall consumption of fat and fibre (p < 0.0005); of fibre (p < 0.0005) – fruit and vegetables (p < 0.0005), wholegrain (p = 0.002): and fat (p = 0.005) – dairy products (p = 0.006) and lean meat and chicken (p = 0.041). There were no significant changes in the consumption of sweet drinks.ConclusionsThis intervention was successful in improving dietary intake in the intervention group participants. The moderate positive outcomes indicate that playgroups potentially provide quite a viable setting to recruit, engage and retain this hard to reach group of mothers of young children in programs that support the adoption of health-enhancing behaviours. This adds valuable information to this under researched area.Trial registrationAustralian and New Zealand Clinical Trials Registry ACTRN12609000718246