The paper examined treasury single account (TSA) and federal government expenditure on infrastructural development in Nigeria. The study adopted Pre – Post Research design. Annual Time series data was extracted from Central Bank of Nigeria (CBN) Statistical Bulletin (2019). Descriptive Statistics was used to ascertain the normality in the distribution of the time series data. Paired sample t-test was used as the data analysis technique with the help of Microsoft Excel programme (version 16). The analysis showed that treasury single account application has positive but insignificant effect on federal government expenditure on healthcare; treasury single account application has positive but insignificant effect on federal government expenditure on education; and treasury single account application has positive but insignificant effect on government expenditure on road construction. Therefore, the study concluded that the application of Treasury Single Account has not improved federal government expenditure on healthcare, education and road construction. The study recommended that TSA account should be maintained, monitored, and well accounted to enable government carry out more of project on education which can improve the manpower development in the country. Also, treasury single account revenues should be used to provide more road construction to Nigerians, particularly in the rural areas, etc.