Demographic, socio-economical, and environmental changes affecting prevalence of Pediculosis capitis. The aim of this study was to investigate the prevalence of P. capitis and external factors affecting the distribution of P. capitis. A total of 6004 primary-school students between 5 and 11 years were screened for P. capitis at 28 different primary-schools in Gaziantep, located in southeastern of Turkey, during different two education terms (First education term is in September 2013 to May 2014, second education term is in September 2014 and May 2015). The prevalence of P. capitis was found to be positive 1.5 % (90/6004) and 6.9 % (415/6004) in first education term and in second education term, respectively. In this study shown that the rate of P. capitis's prevalence was increased 5.4 % in Gaziantep. P. capitis is a neglected infestation and it has re-emerged in Gaziantep, located in the southeastern of Turkey. Health staff member must improve health education programs in primary-school students especially girl students.