This study was designed to measure and explain the relationship between performance appraisal and an increase in productivity of public co-operation employees in Nigeria. The instrument used was questionnaire data collected from workers who constituted the subject of the study. The result revealed that a lack of performance appraisal and performance rating influences the output of a worker adversely. It was also discovered that in some firms their level of productivity increased when they introduced performance appraisal. On the basis of the above finding, the following recommendations were made that a more co-ordinate authority should be established to see that performance appraisals are carried out in individual workers. The managers should avoid bias when carrying on the employees” performance appraisal exercise. This research project will serve as a source of references to students and other researchers who seek to obtain information on the concept of performance appraisal as a means of improving organizational productivity.