Background: Violence has been associated with mental disorder from time immemorial, to the extent that what comes to the mind of most people when mental disorder is mentioned is violence. Majority of the people in the society see mental disorder and violence as inseparable. This has contributed immensely to the stigma associated with mental illness in the society, because people erroneously see mentally ill individuals as dangerous and as a result, will not want to associate with them. Objectives: The objectives of this study are to: identify the type of violent crimes usually committed by the mentally ill offenders; identify the magnitude of psychiatric disorders among the violent offenders and to examine any relationship between psychiatric disorders and violent crimes. Methodology: A total of 400 persons (adults) arrested for violent crimes in three police stations in Ile-Ife/Modakeke area, completed the socio-demographic Data, Clinical and Forensic Interview Schedule, as well as the General Health Questionnaire (GHQ-30), used as a screening instrument. Subjects that scored above the cut-off point on the GHQ, had Present State Examination (PSE) administered on them. Results: About two thirds, 68%, of the subjects were young adults, less than 32years of age, with a mean age of 29.9years (S.D + 7.3). The male to female ratio was 11:1. A higher proportion of them were single (n= 216; 54%); had low education, most did not proceed beyond secondary school, (n= 328; 82%); few were skilled workers (n= 68; 17%); few were civil servants (n= 12; 3%). Majority of the subjects were apparently mentally healthy (n= 364; 91%) while few (n= 34; 8.5%) had a psychiatric disorder. Paranoid schizophrenia was the commonest psychiatric disorder found among them (n= 14; 41.2%). Though non-homicidal offences, especially assaults, were found to be the crime most likely to be perpetrated by a mentally ill subject (n=27; 79%), the proportion of the mentally ill subjects that committed homicidal offence (20.6%), was significantly higher than that of the apparently mentally healthy subjects (7.9%) (P=0.023). The Relative Risk of mentally ill subjects to commit a homicidal offence was found to be about 3 times that of their apparently mentally healthy counterparts. Conclusion: The relationship between mental illness and violent crimes appears not to be as strong as generally believed.