Obesity has been recognised by the World Health Organisation as the most common chronic disease in the world. An increase in the prevalence of childhood obesity has been seen in Poland. The aim of this study was to compare the dietary behaviours, quality of diet, and nutrient intake in a group of obese children compared to children with normal body weight. A total of 105 children aged between seven and 15 years were surveyed. The test group consisted of 52 obese patients from a Dietary Clinic in the Children's University Hospital in Cracow, without accompanying chronic diseases, and 53 normal weight patients. Chil-dren's nutritional behaviours and diet were assessed with a questionnaire (FFQ) and a 24-hour recall. To assess diet quality the Healthy Eating Indicator (HDI) was used. The diet of the studied obese children was rich in highly processed and high-fat products, and poor in vegetables, fruits, and wholegrain products. Obese children consumed on average 73.42 ±19.60 kcal per body weight whereas normal-weight children consumed 49.89 ±12.20 (p < 0.01) and obtained more energy from fat than from carbohydrates. A low intake of vitamins A and D, folic acid, calcium, iodine, and iron in both groups was observed. The HDI showed a low-quality diet in nearly 40% of obese children. Dietary treatment of obese children should concentrate not only on reduction of calories from food products but also on choices of high-nutrient-density products and on developing healthy eating habits.