In this study, the impact of out-of- pocket expenditure on Nigerian health outcomes was examined using annual time series data covering the period (1990-2013). The data was obtained from the central Bank of Nigeria statistical bulletin and World Bank Development indicators. Health outcome is proxy by HIV prevalence. The studyutilize various techniques in order to obtain robust outcome. The augmented Dickey Fuller test shows that the variables are homogeneous of order one..The Johansen co-integration results show that the variables are co-integrated,hence long-run relationship exist among them. The estimated Error Correction Model reveals that public health expenditure does not significantly impact on HIV while the share of out of pocket in health expenditure significantly impact on HIV. Furthermore, both unemployment and per capitaincome significantly impact on HIV. The study therefore recommends that the share of public health expenditure in total health expenditure should be reviewed upward and that alternative source of financing health care outside out of pocket should be initiated.