OBJECTIVE To determine the relationship between healthy lifestyle behaviours of mothers and obesity in their pre-school children. METHODS The cross-sectional study was performed in a district of Istanbul, Turkey, between April and June 2011, and comprised children aged 4-6 years attending public pre-schools and their mothers.. Data was obtained using a questionnaire and Healthy Lifestyle Behaviours Scale-II. Number Cruncher Statistical System 2007 was used for statistical analysis. RESULTS Of the 531 children in the study, 246(46.3%) were girls. Overall prevalence of overweight was 136(25.6%), obesity 77(14.5%)Overweight mothers were 126(23.7%), and obese mothers were 31(5.8%). The mothers of obese children obtained lower scores in the physical activity (p<0.05) and nutrition (p=0.001) subscales, and their total score was also lower (p<0.05).. CONCLUSIONS Lifestyle behaviours of mothers, especially with respect to nutrition and physical activity, may influence obesity among preschool children. Strategies should be developed to improve the physical activity and eating habits of mothers.