Several scales have been used to diagnose and evaluate depression in schizophrenia. However, the association between different depression scales and between depression scales and negative symptoms has not been studied adequately. Sixty-four consecutively admitted schizophrenic patients to Eginition Hospital, Department of Psychiatry, Athens, were assessed on the following scales: the Calgary Depression Scale for Schizophrenia (CDSS), the Hamilton Depression Rating Scale (HDRS), the Expanded Brief Psychiatric Rating Scale-Depression subscale (EBPRS-D), the Positive and Negative Syndrome Scale-Depression subscale (PANSS-D) and the Negative Symptoms subscale (PANSS-N). The depression scales were found to be highly intercorrelated with the exception of the comparison between the EBPRS-D and the PANSS-D. Out of the four depression scales studied, only CDSS and EBPRS-D can discriminate between depression and a PANSS-Negative Symptoms subscale score or negative item scores.