Abstract: This study examines the effect of mothers’ migration status controlling for other proximate factors (socio-economic, environmental and bio-demographic charac- teristics) on under two mortality in Kenya. Data used were drawn from 2003 Kenya Demographic Health Survey with focus on infants and children below two years in age. A total of 5949 infants and children born five years before the survey are used in the analysis. Cox proportional hazard model is used to assess the rel- ative effect of the migration status (migrant or non-migrant) of the mother on survival rates controlling for other explanatory variables. The general results shows that children of migrant mothers especially those of urban-rural migrants face a higher mortality risk compared to those of non-migrant mothers. The results show that failure to account for migration may alter the estimation of urban-rural differentials in childhood mortality.