AbstractBackground.Pediculosis capitis is a worldwide problem. We studied the prevalence of this infestation in Istanbul.Methods.We reviewed the records of the Dermatology Clinic of istanbul University Cerrahpaşa Medical Faculty from a 20–year period (1970–1989).Results.The number of cases of pediculosis capitis have gradually increased over this period, with a peak in 1981. Women are more involved than men. There has been a significant increase in cases in children of school and preschool ages.Conclusions.Many factors may have contributed to this increase: poor hygiene and socioeconomic conditions, lack of medical training, and probably some resistance to pediculicide preparations in the lice. The stigma attached to the disease may prevent people from coming for