Child health is found to have an impact on the socioeconomic outcomes in adult life. Deteriorating child health has been a major concern particularly in developing economies. A great body of literature exists on the determinants of child health; among these, family size is a very important factor which has not been studied much in the light of child nutritional status. The dilution hypothesis suggests that an increase in family size will distribute parental resources unequally among the children with younger kids getting less time and resources. Therefore, this variable is believed to have a negative effect on child nutritional status. However, there are some arguments that the assumption of a fixed and narrow flow of resources from parents underpinning the theory may not always hold. This paper empirically explores the effect of family size on child nutritional status using the Pakistan Demographic and Health Survey 2017-18 data. Child health is measured by three indicators namely HAZ (height-for-age Z score), WHZ (weight-for-height Z score), and WAZ (weight-for-age Z score). For this analysis and to address the issue of endogeneity, the instrumental variable approach is used. Consequently, family size has been instrumented with the gender of the first child (girl). The results suggest that an increase in family size by one child reduces children’s HAZ by 0.205 standard deviation and increases the probability of stunting by 4.4%. The impact on WHZ and WAZ are found to be insignificant. Overall, these results indicate that, while family size may not affect children’s nutritional status in the short-run, it definitely has deteriorating impact in the long-run. Supervisor:- Dr. Muhammad Nasir