The purpose of the study is to explore the influencing factors of the Taiwanese public health nurses' knowledge, attitude and practice inimmunization. A structured questionnaire used in this study was designed by the investigator. A total of 306 subjects were recruited. After statistical analysis, it was found that public health nurses received the highest scores in the area of knowledge on immunization methods; however the lowest scores were presented in the area of contraindication of immunization. In addition, the public health nurses presented, in order, three positive attitudes toward their work as follows: (1) The understanding that immunization can be effective against disease. (2) Confidence in their ability to carry out immunization work and (3) The work of immunization is approved by the general public. Meanwhile the three Leading factors of nurses' negative attitude toward their work are: (1) The worry of unexpected things happening during the process of immunization; (2) The immunization work is too hard to achieve; and (3) The work of immunization is dangerous and the nurses are not protected under the law. The average score to the ability to practicing the work of immunization is 67.9 (total score = 76). So generally speaking, the study show that public nurses' ability of executing the work of immunization was very good. Also, the findings of this study show that factors affecting public health nurses' performance in immunization include: whether or not they taken training workshops in the area of immunization, the classification of the public health unit, immunization knowledge, whether or not they had interest in their professional work, and professional qualification.