The internal structure of a self-report rating scale for depressed mood for schoolchildren - the Child Depression Inventory (CDI) - was examined in both a Russian and a UK sample. The internal reliability and consistency of the scale was high in both samples, and factor analysis revealed that the internal structure of depressed mood was similar in both samples, and further that it was also similar for boys and girls across the two countries. The results support the use of the CDI to measure depressed mood in research with non-Western samples.