The purpose of this study was to describe decision making model of 180 public health nurses in Korea and their knowledge structure for decision making. The differences of decision making models by nurse's knowledge structure were also tested. Research concepts were measured using the instrument based on systemic and interpretive decision making approaches that were developed by Lauri & Salantera (1995). The results were as follows. 1. The public health nurses turned to, most commonly, a mixed practical-theoretical knowledge structure (45.9%), followed by practical knowledge (32%) and theoretical knowledge (22.1%). 2. The six different decision making models were identified. These were named for decision making theories and nursing process. These were client-oriented decision making, rule-oriented systemic decision making, wholistic and intuitive decision making, decision making depending on subjective view and experience, systemic decision making for defining problems, and hypotheticodeductive decision making for defining problems. 3. The public nurses who had practical and practical-theoretical knowledge structure and community health practitioner (CHP) retold that decision making depends on subjective view and experience. Also the public health nurses who had 5~19 years clinical experience represented hypothetico-deductive decision making for defining problems.