This study examines whether family income in early childhood is related to achievements of Israeli students in standardized tests at primary school. We analyzed data from the Israeli censuses of 1995 and 2008, which include information on family income and socio-economic background of children along with data pertaining to their achievements in standardized tests taken in fifth-grade. The findings show that belonging to the lowest quintile of family disposable income in early childhood had a negative and significant effect on future educational achievements, controlling for family income in late childhood and other socio-demographic variables. Furthermore, the effect of family income was stronger when measured at birth -- age two, than at ages 3-5. These findings are consistent with the claim that child development is most sensitive to environmental influences in the very first years of life.