Currently, there is not an Spanish instrument suitable to evaluate obsessive-compulsive symptomatology. The objective of this study was to translate and test reliability of the Yale-Brown Obsessive-Compulsive Scale (YBOCS). This scale has been designed to quantified severity of obsessive-compulsive symptomatology in patients with obsessive-compulsive disorder (OCD), as well as to evaluate treatment response. One hundred and five interviews were rated by 3 psychiatrists on 35 patients with OCD. Interrater reliability were significant (p < 0.001), with a mean correlation of 0.88. Cronbach's alfa coefficient for each ratter were in a range of 0.84 to 0.87, with a mean of 0.85, showing that the interview is homogeneous. Also, should be mentioned that interrater reliability and Cronbach's alfa coefficient were done in 12 items instead of 10 according to the original version. However, we can conclude that the Spanish version behaved in a very similar fashion to the original scale.
