Chronotype refers to the time of the day that a person's physical and cognitive functions are active. Simply this is a circadian phase preference of a person. While some of the people are morning active (so called larks) others are more active at nights (The owls). The study of circadian rhythms, known as chronobiology, is all about the metabolic and psychiatric differences between people who have different chronotypes. A few tests are used to determine chronotypes. The CCTQ (Children's Chronotype Questionnaire) is a parent-report, 27-item mixed format questionnaire measuring chronotype of children in multiple domains : the midsleep point on free days (MSF), a morningness/eveningness scale(M/E) score, and a five-point chronotype (CT) score. The aim of this study is adapting Children's Chronotype Questionnaire (CCTQ) into Turkish language and validating the instrument in Turkish population. 101 children aged nine through eighteen constitude the sample of the study. The sample was composed of clinical (n=51) and community groups (n=50). CCTQ and Morningness Eveningness Scale for Children (MESC) questionnaires were applied to children and parents, then the CCTQ and MESC scores were compared to examine the validity of CCTQ. The internal consistency and external validity of the Turkish CCTQ was sufficient to compare MESC-Turkish. As a result of this research carried out in accordance with methodological research principles, correlation between the M/E scores of CCTQ and MESC was significant. The Turkish version of CCTQ has been found to be valid and reliable in Turkish children.