The purpose of this study is to analyse the effectiveness of Integrated Financial Management Information System (IFMIS) on performance of public sector in Nigeria. Public finance management has come under immense scrutiny by donor community as well as general public in a call for enhanced accountability of government expenditures for improved public service delivery. The study reveals that there was a positive relationship between the effectiveness of IFMIS on public financial management and the independent variables; financial reporting, budgeting, internal controls and government projects as 72.4% of the effectiveness of IFMIS was accounted for by study independent variables. The relationship gives 95% confidence level of effectiveness. The study recommends that IFMIS be enhanced and improved at system development level so that it gives real-time figures and factors in other functions/operations for better service delivery.