Objective: The purpose of present study is comparing quality of life in severely mental retardeds lived in home and residential center. Method:In this cross sectional study 225 severely mental retardeds in Tehran providence selected as random- clustered sampleling method. One of parents or care giver answers to Cumines quality of life questionnaire in both groups. Results: Non parametric Mann Whitney U test showed that quality of life of severely mental retarded in home significantly is better than residential centers. Conclusion:Based on our findings caring mentally retarded in family caused promotion of their quality of life.