Investing in child health is successful means of developing human capital and bringing intergenerational equity. Considerable sum of money is sourced from national exchequer to provide easy access to vaccines at zero price for all babies in Pakistan. Under-utilization of service causes economic loss. This thesis identifies patterns of vaccine-acceptability in four provinces of Pakistan and socio-economic conditioning of parental behavior, when access is constant. It is mixed method cross-sectional study aimed at providing market intelligence to government to help improve programming yields. Variables were selected and defined from PSLM 2014-15 datasets. Three categories of dependent variable are taken, i.e. households with at least one baby who is fully immunized or never received immunization or dropped-out of schedule. The independent variables of study are: Province, Region, District, Language of parents, Occupation of parents, Perinatal care, Place of delivery, Over- crowded household, Wealth status, Hygiene in home, Satisfaction level with primary health service. Descriptive statistics are provided to explain the analytical sample. Multiple predictors are regressed against categorical responses in conditional logit model. Principal factors are confirmed in multidimensional structure. Vaccine related behaviors of caregivers and modifiers are assessed qualitatively. In KPK, concern for side-effects and perceived risks of vaccination result in parental refusal. The behavior is associated with low prevalence of education in mothers, low utilization frequency of all government services and reluctance to retain vaccination cards. Across districts of Punjab, vaccine refusals are due to lack of convenience in seeking vaccine. The determinants are frequency of Lady Health Worker visits and occupation in farming. Divorced daughters living with parents are more likely to be hesitant. In Sindh, perceived utility in vaccines depend on lack of convictions. Refusal is correlated with home births, male gender of child and unhygienic conditions. In Baluchistan, complacency to traditions forms the basis of vaccine refusal. It is because of strong adherence to religious and tribal norms. The correlates are low wealth status, dependence on farming occupation and poor quality of postnatal care. Acceptability of vaccination is function of multidimensional socio-economic determinants. Entwined social factors cause parents to rationalize decision of refusing vaccines which is not in best interest of children. A vaccine-behavior model is approached inductively using interpretivism. Government programming for immunization can minimize costs by acknowledging behavioral determinants and adopting targeted approaches. Supervisor:- Dr. Nasir Iqbal