The study evaluated the effect of employee turnover on organizational performance of manufacturing firms in Enugu Metropolis. Specifically, the study sought to: ascertain the effect of employee downsizing on operational safety of manufacturing firms in Enugu Metropolis and examine the effect of voluntary resignation on physical expansion of manufacturing firms in Enugu Metropolis. The study adopted descriptive research design. The study area was Enugu State. The sample size of 358 respondents was taken from population of 503 staffs of the selected indigenous manufacturing firms in Enugu metropolis The research question were answered with simple percentage, mean and deviation. The hypotheses were tested with single regression. The empirical results showed that employee downsizing has negative and significant effect on operational safety of manufacturing firms in Enugu Metropolis (t-statistic; -6.446; P-value; 0.000 < Sig-value; 0.05) and voluntary resignation has negative and significant effect on physical expansion of manufacturing firms in Enugu Metropolis (t-statistic; -11.826; P-value; 0.000 < Sig-value; 0.05). The study recommended that management of the manufacturing firms in Nigeria should introduce policies that would address issues or factors that could cause labour turnover in their organizations. Also, employees should be adequately motivated so that their services can be retained over a reasonable period of time.