A study of the socio-economic and diagnostic profile of psychiatric patients treated at a mental hospital in Nigeria over a period of six months was conducted. Schizophrenia, organic psychosis, and mental sub-normality were found to have been diagnosed more often among under privileged persons from lower socio-economic classes; while affective disorder (manic depression) and neurotic illness were commoner among persons from economically more fortunate higher social classes. Males exceeded females in the cohort and the patients generally exhibited upward social mobility when compared with their parents. Possible socio-cultural factors contributing to the findings have been discussed. A suggestion is made for a more elaborate field work to study the relationship between socio-economic class and psychopathology in a developing country like Nigeria.