Objectives. The aim of this pilot study was to assess the prevalence of co-morbidity in obese children. Particular emphasis was on cardiovascular risk. Method. In this retrospective, cross-sectional, observational study the data of 155 obese children, who visited a paediatric obesity outdoor clinic, have been studied. Results. In all, 92% of the population had at least one cardiovascular risk factor. In all, 48% showed a high systolic and 9% a high diastolic blood pressure, while 18% had an increased fasting glucose. In 60%, we diagnosed insulin resistance: the homeostasis model assessment was elevated. Discussions. The prevalence of high blood pressure, dyslipidaemia, abnormal fasting glucose and insulin resistance are high in this retrospective study. Outcomes of foreign studies on this object are difficult to compare because various populations and cut-off points are used. A new, prospective, study will be conducted to asses the prevalence of co-morbidity in obese children in general practice.