The major focus of the study is to investigate the supplier selection criteria and its effect on procurement performance in county governments. The specific objective was to examine the effect of supplier’s past performance on procurement performance in county governments. Descriptive research design was applied in the study. The study population was 168 that included professional employees working in the county government departments of Murang’a and Kirinyaga counties. Purposive sampling was preferred in selection of the sample size of 60 respondents who were the heads of the departments. Data collection tool was self-administered questionnaires. Both descriptive and inferential statistics were used to perform data analysis. The results of the model summary indicated that R2 equals 0.642, thus revealing that 64.2% of the procurement performance in county governments can be attributed to supplier’s past performance. The study concludes that there is a positive strong effect between supplier’s past performance and procurement performance. The study recommends an effective scrutiny on supplier’s past performance before awarding contracts by carrying out due diligence to minimize uncertainties arising from supplier failure to execute complex contracts that require a given level of expertise