Background: Depression is the most common mental health disorder, a disease that that involves the body, mood and thoughts. It is often under diagnosed, especially among elderly people in the nursing home setting. The objective of this study is to determine the prevalence of depression among the elderly people in the nursing home setting, Bangkok, Thailand and identify factors associated with depression. Methods: Cross-sectional study was conducted among 237 participants above the age of 60 at Ban Bangkhae nursing homes; Bangkok Thailand, The measurement tools consisted of Thai Geriatric Depression Scale, UCLA Loneliness Scale (ULS) and other related questionnaires. Multivariable linear regression was used to find association between depressive symptoms and factors with statistical significant of each analysis against the p-value 0.05. Results: The prevalence of major depression was 7.2% and the prevalence of minor depression was 32.1%. The adjusted R Square is 0.413, and F value is 33.873 (p value <0.001) and the Durbin-Watson is 1.746. Loneliness (β = 0.54, P < 0.001), Insomnia, (β = 1.85, P < 0.002) and Lack Social Activity (β = -0.39, P < 0.001) Inadequate of Vitamin D (β = -1.45, P < 0.014) and physical activity (β = -1.46, P < 0.021) associated with depression where (β) is the regression coefficient. Insomnia, loneliness, Physical Activity, Inadequate Vitamin D and Social Activity were found to be the prominent factors with depressive symptoms among Ban Bangkhae nursing homes setting. Limitation: Unforeseen flooding natural disaster from October and December 2011 may have overestimate of the prevalence of depression. Conclusion: The prevalence of depressive symptoms 39.1% was high in comparing to the findings in Thai community dwelling elderly. Insomnia, loneliness, Lack of social Activity, Physical Activity and Inadequate Vitamin D were identified as important factors to emphasize when assessing for depression in the nursing home setting. The findings of this study will assist in developing adequate prevention and treatment strategies among the elderly in the nursing home population.