This study provides an in-depth analysis of domestic and external health financing situation in Nigeria by disease-specific conditions between 2010 to 2018. Key health financing agents in the country include households, firms, government, donors, and non-profit organizations. . The study adopted the descriptive analytic approach and the Pearson correlation analysis. It considers the correlation between donor expenditure per disease area and general government health expenditure. The study revealed that between 2010-2018, total expenditure by diseases was $72.92 billion. Further analysis by the core priority interventions shows that total expenditure on malaria was $29.0 billion, followed by non-communicable diseases (NCDs) $6.9 billion, while human immunodeficiency virus (HIV) treatment consumed $6.5 billion. Tuberculosis (TB) expenditure was $2.7 billion and Neglected Tropical Disease (NTDs) was $0.2 billion. The study found a strong correlation between aggregate donor expenditure and aggregate Federal Government (FG) expenditure (r=0.6), a medium correlation between the donor and State Governments (SG) expenditure (r=0.3), and a small correlation between donor and Local Government (LG) expenditure (r=0.2). However, disaggregating by disease intervention, the study showed that there is a small correlation between FG HIV and FG Reproductive Health (RH) expenditure and no correlation between FG malaria expenditure and donor malaria expenditure. On the contrary, the study finds a strong correlation between donor expenditure and (SG) HIV and SG RH expenditure and a small negative correlation between donor malaria expenditure and SG malaria expenditure. These findings indicate that while overall FG expenditure increases as donor increases financing, this increase may not be related to HIV, Malaria, and RH programming. However, donors are willing to work with state governments who are ready to put in more money for health especially for HIV and RH, and not necessarily for malaria. Thus, the study recommends that government should increase intervention/program targeting especially on Malaria as well as TB, and HIV.