Court-selected defendants remanded for diagnosis in custody are kept under observation in a psychiatric observation unit from 7 to 21 days and are examined by psychiatrists from 4 to 10 times. Because of concern that excessive numbers of defendants are remanded in custody for such diagnoses before sentencing, researchers reviewed the diagnosis, medical recommendation, and fitness-to-plead findings for each of the 607 defendants assessed from April 1978 through March 1980 at an observation unit. The results showed that over half of the persons examined were not mentally disordered and that a diagnosis was possible in less than half of the sample. Most of the defendants were between the ages of 19 and 39, and schizophrenia was diagnosed in the majority of cases involving mentally ill remands. One-third of the total sample had a history of previous psychiatric consultation, and of those found to be mentally ill about 60 percent had had contact with psychiatrists before. While the defendants had been charged with a varienty of crimes, schizophrenics who had committed nonsexual personal offenses formed the largest subgroup. On the whole, the schizophrenics were most likely to be recommended for a medical disposal and to be allowed by the court to participate in the treatment proposed. The court followed the psychiatrists' recommendations in 89 percent of all cases diagnosed. Remand on bail rather than in custody and a closer study of the psychiatrists' role in the legal process are recommended. Related studies are reviewed. Data tables and an 18-item reference list are included. (Author abstract modified)