The prevalence of adult obesity in Kuwait is among the highest in the Arab peninsula, and cardiovascular disease, for which obesity is a risk factor, is the leading cause of death. This study reports familial and environmental factors associated with childhood obesity; in addition to adverse effects of obesity on children's serum lipids, lipoproteins, apolipoproteins, insulin, and blood pressure profiles. The authors carried out a pair-matched case-control study including 460 obese (body mass index >90th percentile of the age/sex specific reference value of the National Center for Health Statistics), school children 6 to 13 years old matched by age and gender to 460 normal weight controls. We ascertained obese children in a cross-sectional survey of a representative sample of 2400 school children selected from 20 schools by multistage stratified random sampling. Biochemical variables and blood pressure were adversely affected in obese children. The conditional logistic regression analysis showed that family history of obesity, and diabetes mellitus, respiratory and bone diseases in child were significant associated factors with obesity after adjusting for social and behavioural factors. Physical activity and parental social class were not significant. We recommend early preventive measures with emphasis on families in which one or both parents are overweight.