Background: Competence is a fundamental component of nursing care and plays an important role in the quality of services provided by nurses. Aim of study: The aim of the study was to evaluate the effect of small-group teaching on nurses’ competency level regarding patients undergoing cholecystectomy at Zagazig University Hospitals. Research Design: A quasi-experimental research design was used to achieve the aim of the study. Study setting: The study was conducted in Internal and General Surgery Department in New Surgery Hospital at Zagazig University Hospitals. Sample: A convenience sample of 30 nurses working in Internal and General Surgery Departments in New Surgery Hospital was included. Tools of data collection: Two tools were used: first, a self-administered structured questionnaire (pretest/post-test); and second, observational checklist. The study was implemented in eight months from May 1, 2019 to the end of December 2019. Results: There was a statistically significant improvement of nurses’ knowledge after implementation of small-group teaching, with mean±SD of 22.83±0.59, than before, with a statistically significant difference (P=0.00). Moreover, there was a statistically significant improvement of nurses’ competency level after implementation of small-group teaching, with mean±SD of 241.86±3.49, than before, with a statistically significant difference (P=0.00). Moreover, there was a positive correlation between total nurses’ level of knowledge and their level of competency. Conclusion: It can be concluded that small-group teaching for nurses had a positive effect on improvement of nurses’ knowledge, which reflected then on improvement of their competency level. Recommendation: Continuous in-service training programs are recommended to improve and maintain nurses’ competency level regarding patients undergoing cholecystectomy. Keywords: Cholecystectomy, Nurses 'Competency, Small-group Teaching