Background: Performance appraisal system is developed to provide justification for career development, accountability, recognition, promotion, compensation, discipline and increase in remuneration. Performance appraisal system must be identified by staff nurses that affect their commitment. Aim of the study: Was to assess performance appraisal system as perceived by staff nurses and its relation to their commitment. Design: Descriptive correlational design was utilized to achieve the aim of present study. Setting: This study was conducted at Benha university hospital at the intensive care units. Sample: The study included all 200 staff nurses who were working at the above mentioned setting during the time of the study and have at least one year of experience in their work setting. They are distributed in the work setting. Tools: Two tools were used for data collection namely performance appraisal system questionnaire and staff nurses' commitment questionnaire. Results: 68.0% of studied staff nurses had high perception of performance appraisal, while 56% of them had high commitment. Conclusion: There was statistically significant positive correlation between performance appraisal system and commitment among the studied staff nurses. Recommendations: Attending and participation in training programs and decision making to keep commitment level high, Continuous education to cope with changes that happen daily in nursing field and developed performance appraisal systems and continuous supervision and appraisal interview should be conducted with nurses through daily and weekly discussion by their immediate supervisors to discuss their job performance to learn more and develop their knowledge and skills.