This paper presents a social work study to investigate depression and mental ability among elderly people who live in institutional elderly versus nursing home residents. The study designs a questionnaire and distributes it among 345 elderly people who live on both places. The study uses Wechsler Memory Scale (WMS) test where mental ability contains seven factors including “general information”, “orientation”, “mind control”, “logical memory” and “repeated figures”, “visual memory” and “learn association”. We have performed some statistical tests and the results show that there is not any meaningful difference between two groups of people in terms of mental utilization when the level of significance is five percent. However, in terms of seven scales, there are some meaningful differences on “general information” and “visual memory” between two groups. The study also shows that there is a meaningful difference between two groups of people in terms of “depression level” when the level of significance is five percent.