Background: Nursing care standards are general guidelines that provide a foundation as to how a nurse should act and what she should or should not do in her professional capacity and also influence on their performance. Purpose of the study: Was to assess the effect of nursing care standards on staff nursing performance in surgical care units through: assessing the actual nursing care standards in surgical care units, implementing the nursing care standards and evaluating the effect of standards on nursing performance after the implementation. Design: Quasi-experimental research design was used: the study was conducted in surgical care units (critical and intermediate) at National Liver Institute Hospital. Sample: All staff nurses (65) working in surgical care units (critical and intermediate) were involved in the study. Instruments: Data were collected using Observational checklist for assessing the process standard pre and post implementing nursing care standard. Results: There wasn't statistically significant difference in process standards in surgical care units. There was statistically significant difference in the total mean process scores regarding all items of nursing practice pre & post implementing the nursing care standards for patients in critical care units. There was highly statistically significant difference in the total mean process score regarding all items of nursing practice pre & post implementing the nursing care standards for patients in intermediate care units. Conclusion: Nursing care standards affect staff nursing performance Recommendation: The study results should be disseminated to the important key persons and healthcare agencies to be considered.