To describe parental concerns about their child's weight, to determine the proportion of parents taking preventive action to avoid obesity in their children and the predictors of taking preventive action, and to describe the strategies adopted by parents.

A cross-sectional survey was conducted. Children's heights and weights were measured, and parents completed a questionnaire that included measures of their own weight status, perceptions of their child's weight, concerns about their child's current weight and future weight as an adolescent and adult, and the strategies used to prevent obesity.

The study was conducted in Melbourne, Australia.

A total of 291 families of children aged 5–6 years and 919 families of children aged 10–12 years participated.

Eighty-nine per cent of parents of overweight 5–6-year-olds and 63% of parents of overweight 10–12-year-olds were unaware their child was overweight. Seventy-one per cent of parents of overweight 5–6-year-olds and 43% of parents of overweight 10–12-year-olds were not concerned about their child's current weight. Although 31% of parents of 5–6-year-olds and 43% of parents of 10–12-year-olds were taking action to prevent unhealthy weight gain in their children, less-educated parents were less likely to do so.

Public health programmes are required to raise parental recognition of childhood overweight and of related risk behaviours, and to provide parents with practical strategies to prevent unhealthy weight gain in their children.