The purpose of this study was to determine the prevalence of orthorexia nervosa in dietitians, as assessed by administering ORTO-15, Eating Attitudes Test-40 (EAT-40) and Maudsley Obsessive-Compulsive Inventory (MOCI). Our study included 117 dietitians (Ankara). Orto-15 test scores below 40 points was considered indicative of orthorexia, while higher scores indicated a normal eating behavior. It was found that participants with ORTO-15 scores less than 40 had higher scores for EAT-40 and MOCI (p < 0.05). The results showed a significant negative correlation between the ORTO-15 and EAT-40 scores and BMI values. In that respect, further investigation with dietitians into orthorexia nervosa is recommended.