Objective: The aims of this study were to assess the prevalence of activity limitations in school age children with chronic health conditions/impairments and to determine the affecting factors in Kayseri, Turkey. Material and Methods: This cross-sectional study was conducted in Kayseri, Turkey, in 2006. A questionnaire was given to the parents of 4508 children aged 7-17 years, selected randomly from 20 primary schools out of 99. Disability was defined as a long-term inability in social role activities in normal function or school, due to a chronic physical or mental health condition during the previous year. Results: Out of 4508 children aged 7 to 17 years, 35.3% had one or more chronic health conditions while 3.7% had activity-limiting conditions. The rate of activity limitations was 9.2% in children with chronic health conditions, which was significantly higher than their healthy peers (0.8%). Activity-limiting conditions were higher in children with low-educated and low-income families. They were also more common in children with teeth and periodontal diseases, visual impairment, speech impediments and psychiatric/nervous problems. Conclusion: Activity-limiting conditions in school-aged children with chronic health conditions are major public health problems. Long-term chronic health conditions and bad family and environmental factors are significant risk factors for activity limitation. Targeting on prevention and rehabilitation efforts in such children and families may be an important way of decreasing the impact of chronic conditiens.