BACKGROUND Pain assessment and management are imperative parts of nursing care and considered as one of the most fundamental patient rights. The role of pain management education is well established in improving knowledge and attitude among nurses. OBJECTIVE This study aims to evaluate the impact of pain management educational program on the knowledge and attitudes of intensive care unit (ICU) staff nurses toward pain assessment and management. The baseline score of pain assessment and management knowledge and attitude of ICU nurses has been identified in a previous research, and the result showed immense lack of knowledge and poor attitudes among ICU nurses toward pain assessment and management when dealing with ICU patients. METHODS This is a pretest-posttest experimental study, utilizing a self-reporting questionnaire tool to obtain information about nurses' knowledge and attitudes toward pain assessment and management after implementation of new pain management educational program for critical care nurses. Data were collected using the Knowledge and Attitudes Survey Regarding Pain tool that measures knowledge with 22 question items and measures attitude with 17 question items. Paper-based questionnaire was distributed to nurses for data collection. CONCLUSIONS The results showed significant improvement in knowledge and attitudes about pain assessment and management among ICU nurses; it was evident after delivering pain management education program. At baseline, 204 ICU nurses gave consent and completed the questionnaire and thus included in baseline measurement before implementing the intervention. In the postintervention measurement, the questionnaire was distributed to the same participants included in the baseline phase from which 181 participants completed the questionnaire for the second time, with a response rate of 89%; the deficits and preconception in pain assessment and management can be improved through implementing pain management educational programs.