The elderly residence in nursing homes in Iran has a growing trend and maintaining and promoting the mental health of this vulnerable group is of great importance. The present study was conducted in order to identify the prognostic factors of mental health in Elderly resided in geriatric centers. Methods: This cross-sectional study was conducted during summer 2007 on 56 elderly resided in the Golabchi nursing home in Kashan. The participants were selected using purposive sampling method. They had normal IQ, were able to understand the questions, and had no psychosis, no known psychological disorder and Alzheimer. The study was undertaken using a 28-article form of the standard general mental health questionnaire (GHQ-28) and a researcher-made questionnaire including the demographic and personal questions. After data extraction, the data was progressively analyzed using SPSS 16 software, and using statistical tests including Chi-square and multivariate linear regression analysis. Results: 41.1% of the samples lacked mental health. The mental health status showed a significant correlation with the previous agreement to stay in the nursing home and Quran recitation while staying, but didn’t have any significant correlation with age, sex, marital status, the reason of residence in the nursing home, educational level, previous residence of the relatives in the nursing home, and satisfaction with staying there. 55.4% of the score variance of elderly mental health (p<0.001; F=11.16) was explained by three variables of religious activities while staying in nursing homes, education and previous agreement with staying in nursing home. Conclusion: providing the necessary facilities for religious activities and drawing the agreements of the elderly in order to stay in the nursing home help the promotion of mental health of the elderly who reside in nursing homes.