The reliability across time, informants and interviewers of the Spanish translation of the DISC-2.1 was tested on a Puerto Rican Hispanic sample using a test-retest design. Levels of reliability between clinic and community samples and between younger and older children were compared to explore the sources of low reliability for certain psychiatric disorders. Parents' reports tended to be more reliable than those of their children, although the difference was less obvious with older children. Reliability was generally higher for the externalizing disorders and when the second interviewer was a psychiatrist rather than a lay interviewer.