The issue of payroll fraud in public institutions in Nigeria has demonstrated a huge economic burden, with minimal political will to address it. Interestingly, the level at which this fraud has been evaluated has been inconclusive. Hence, this study investigated the assessment of the Integrated Payroll Personnel Payment System on Personnel Cost-fraud in Nigeria.   Adopting the two-stage Least Squares (2SLS) approach for estimating the longitudinal time series data from 1993 to 2023, sourced from the World Bank development indicator, and the Nigeria Bureau of Statistics, was necessary. The result revealed that for every additional employee (lnemployee), personnel cost ( lnpersonnelc~t)  increases by 2.370815, at 23.7 percent at the 5% significance level since the p-value is less than 0.05. Also, for every additional payroll fraud (lnpayrollfraud) made, the personnel cost ( lnpersonnelc~t) goes up by  .2073029, which is 2.1 percent at the 5% significance level since the p-value is less than 0.05. While federal government recurrent expenditure (lnGvtRecuxp) reduces personnel cost by .2719514, which is at 27 percent at the 5% significance level since the p-value is less than 0.05. An independent regulatory agency needs to monitor the activities of an integrated Payroll Personnel Payment System with periodic verification to strengthen the system. The need for parliamentary legislation that permits desk officers at the state level, and Periodic verification, is necessary to strengthen the integrated payment system in Nigeria. 

Keywords: Integrated System, Personnel, Payroll, Public Sector, & Fraud