Objectives: Nurse managers are central to health delivery in South Africa. However, there is a paucity of research that analyzes their competence to successfully discharge their managerial role. To identify the competencies perceived to be important for effective nursing management in the South African public sector and the managers' self-assessed proficiency in these. Design and Sample: A cross-sectional survey using a self-administered questionnaire. 215 senior nursing managers at South African public sector hospitals. Measures: Respondents rated the level of importance that 51 proposed competencies had in their job and indicated their proficiency in each. Results: Public sector managers ranked controlling as the most important competency, followed by leading, organizing, and self-management. Health/clinical skills, planning, and legal/ethical competencies were ranked as being relatively less important. They assessed themselves as being most competent in self-management, followed by planning, controlling, leading, and specific health skills. The competency gap was the largest for legal/ethical issues, organizing, and controlling. The competency gap for planning and self-management was relatively smaller. Conclusions: This research confirms that there is a lack of management capacity within the public health sector and also identifies the areas in which the lack of knowledge or skills is most significant. © 2011 Wiley Periodicals, Inc.