Objective To assess the oral health status and treatment needs in a group of hospitalized chronic psychiatric patients. Method The dental status was assessed using the DMFT index. Demographic and medical data were retrieved from the institutional clinical files. Results 491 patients were examined in the study. 258 (52.5%) of the patients were males. The mean age was 52.3 +/- 12.3 years and the average length of hospitalization was 17.5 years. The majority of the patients (69%) were diagnosed with schizophrenia. The mean DMFT was 19.25 +/- 7.85. Missing teeth (81.4%) comprised the largest proportion of the DMFT while filled teeth (0.5%) the smallest. 18.1% of the DMFT consisted of decayed teeth. Stepwise logistic regression analysis showed that the DMFT significantly increased with age (p<0.001) and was significantly higher in schizophrenia patients than those with mental retardation (p<0.01). Males had significantly higher decayed teeth (p<0.01) and fewer missing teeth (p<0.01) than females. 58 dentate subjects (14.4%) were caries free. Two hundred and thirty five patients (58.5%) required restorative care, the mean number of treatments required per patient was 1.42 +/- 1.82. Eighty-nine subjects (18.1%) were found to be completely edentulous with only 17 wearing complete dentures. 70.6% of dentate patients needed tooth extraction for caries and 36.1% for periodontal disease. Conclusion The findings of this study demonstrate poor oral health status with extensive unmet dental and prosthetic needs. These underline the urgent need for specific preventive oral health programme to improve the dental care of these chronic psychiatric inpatients.