This study aims to understand how much of the gender gap in hospitalization expenditure is explained by different socio-economic, demographic and health-care related factors across the age-groups with a particular focus on the elderly. The unexplained part of the gap (the coefficient effect) is assumed to arise purely due to gender bias. Gender inequality in health-care expenses has been well-documented particularly in case of developing countries and also for India separately. The current study contributes to the existing knowledge by analyzing the gender gap across the age-groups and by bringing to notice how the severity of gender disparity and the importance of different determinants vary across the age-groups. Using the 71st Social Consumption: Health Survey of NSSO, conducted during January to June in 2014, the study finds that on overall the coefficient effect comprises around 50% of the total gender gap, indicating large gender bias in hospitalization expenses. Also a large part of the endowment effect (the explained part) is suggestive of an implicit form of gender discrimination as the differences in choices between men and women influencing hospitalization expenses like the choice between public and private health-care providers, whether to avail of services like x-ray, diagnostic tests or not, indicate that women health-care needs are often put on the lower end of the priority list of households. The gender gap and also both the implicit and explicit forms of gender discrimination are found to be highest among the elderly. Unlike few other age-groups, where the ailment pattern explains a lot of the gender gap, ailment patterns are similar for the elderly men and women. Apart from education level and the implicit form of gender discrimination accounting for a large part, the multivariate analysis suggests marital status to be a significant explaining factor for the gender gap among the elderly. Among the elderly, more women suffering from widowhood leads to economic deprivation being reflected in less hospitalization expenses as compared to men and explains the gender gap significantly.