Studies on the relation between socio-economic factors and metermal and child health have found that poverty, lack of edcation, inappropriate health serives are affecting to maternal and child health. The Gender Related Development Index (GDI) focuses on equality between men and women as well as on the average achiement of all people taken together, using same cariables as the Human Development Index (HDI) which are life expectancy, literacy rate, and per capita GDP. This research is to inverstigate whether HDI and GDI are useful determinants for maternal infant mortality. Using 146 UN member countries date, we condented multiple regression analysis for maternal and infant mortality with three models which are Model(individual variables-literacy rate, per capita GDP), Model(HDI) and Model(GDI). The results showed that HDI and GDI are powerful determinants of both maternal and infant mortality, respectively HDI($eta$=-1.18, t=3.3; $eta$=1.04, t=5.1) GDI($eta$=-1.44, t=3.9; $eta$=1.28, t=6.5) The higher power in model with GDI for both maternal and infant mortalities represented that GDI was more powerful determinant of maternal and infant mortality, than HDI respectively HDI($R^2$=0.824, $R^2$=0.842), GDI($R^2$=0.834, $R^2$=0.865). In conclusion, the maternal and infant mortalities are explained by GDI than HDI and may be lower in the societies where there are less discimination between men and women.