Doctors sometimes assess allegations of ill-treatment. Reports from such examinations may be used if the practice of the police is to be appraised: they should therefore be relevant and exhaustive. We assessed, retrospectively, the quality of 318 medical documents concerning 100 persons held in central police stations in Madrid, Spain, from 1991 to 1994. In 71 documents concerning 44 persons the doctors quoted the detainee as alleging ill-treatment. Most of the documents appeared to lack significant information on history of ill-treatment and description of the clinical examination. Of 34 conclusions, ten were unacceptable and the premises were insufficient in 16. These observations point to weaknesses and needs for improvements in the fulfillment of the role of doctors as safeguards of the rights of detainees. Medical examinations should be conducted outside the control of police officers, by a neutral doctor using a check-list/protocol. The quality of the report should fulfill international standards.