BACKGROUND CONTEXT: Studies have shown that adolescent idiopathic scoliosis (AIS) prevalence varies between 0.35% and 5.2% and it is generally accepted as an average of 2%-3% in children under age 16. There are a few narrow-scope studies based on school screening performed on the epidemiology of AIS in Turkey. Prevalence rates reported by these studies are lower than reported in neighboring countries. Of note, they were conducted in single cities, generally based on small sample size, and are different from each other in terms of methodology and age groups. The present study was conducted based on a large population in 85 schools of 40 provinces in Turkey.