Inadequate fruit and vegetable consumption is associated with increased chronic disease risk and represents a considerable global health burden. Despite evidence that dietary habits track from early childhood, there are few published trials of interventions attempting to increase preschoolers' fruit and vegetable consumption.The Healthy Habits trial aimed to assess the efficacy of a telephone-based intervention for parents to increase the fruit and vegetable consumption in their 3-5-y-old children.A cluster randomized controlled trial was conducted involving 394 parents of children aged 3-5 y recruited through local preschools. Parents allocated to the intervention received printed resources plus four 30-min telephone calls targeting aspects of the home food environment associated with children's fruit and vegetable consumption. Parents allocated to the control group received generic printed nutrition information. Children's fruit and vegetable consumption was assessed by using the Fruit and Vegetable Subscale of the Children's Dietary Questionnaire, which was administered via telephone interview at baseline and 2 and 6 mo later.Analysis of all available data showed that children's fruit and vegetable scores were significantly higher in the intervention group than in the control group at 2 mo (P < 0.001) and at 6 mo (P = 0.021). Sensitivity analysis using baseline observation carried forward showed an intervention effect at 2 mo (P = 0.008) but not at 6 mo (P = 0.069).Telephone-delivered parent interventions may be an effective way of increasing children's fruit and vegetable consumption in the short term. Further investigation to determine whether the intervention effect is maintained in the longer term is recommended.