One of the most intriguing results concerning chronopsychological effects at school is the worse school performance in evening-oriented adolescents. The study intends to correlate affective state with chronotype. Therefore, we carried out a field study in adolescents in a natural setting (in school) and assessed their actual affective state during the very first lesson at school (8:00?a.m.). A total of 97 pupils (60 boys and 37 girls; mean age 13.14 ± SD 1.84; range 10-17 years) from class Grades 5, 6, 8, 9, and 10 participated in this study. We used the Composite Scale of Morningness (CSM) to assess morningness and the Adjective Checklist for Children (EWL40-KJ) to assess mood. Morningness was positively associated with relaxation, good mood, and activation, and negatively related to bad mood, anger, and deactivation. No significant relationship was found related to excitation, aggression, anxiety, and depressiveness. Concerning the two general dimensions, CSM scores were positively related to positive mood and negatively to negative mood.