Objective: This study compared personal well-being of children with mental retardation in north of Tehran and Hamadan, and examining the likely relationship between personal well-being of children and their mothers. Method: 356 pair of mother-child participants were recruited randomly (43.8% from Hamadan and 56.2% from Tehran). Personal Well-being Index-Adults (Cummins, 2005) and Personal Well-being- Intellectual Disability Form were administered.  Results: No significant difference was observed between the children, and their mothers in these two cities. However, children with mental retardation in Hamadan showed higher scores in personal well-being in comparison with their peers in north of Tehran. Conclusion: There exists a relationship between personal well-being of children with mental retardation and their mothers.