Abstract: Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of morbidity and mortality throughout the world, resulting in a substantial and increasing economic and social burden. The aim of the present study was to assess knowledge, practice, and self efficacy for patients with COPD. A descriptive research design was used in this study. The sample consisted of 100 patients with COPD at the outpatient clinic of Respiratory Medicine, Mansoura University Hospital. Three tools were used to collect data, A structured interviewing questionnaire consisted of patient's sociodemographic characteristics and patient's medical history, patient's knowledge and practice questionnaire, and self-efficacy scale for patients with COPD. The results of the present study concluded that 96%, 93%, and 86.0% of the studied subjects had low self efficacy, unsatisfactory knowledge, and unsatisfactory practices scores about COPD respectively. There was a significant statistical relation between patients' occupation and their total knowledge scores, and between patients' occupation and their total practice scores. However there was no significant statistical relation between patients' knowledge, practice and their self efficacy. The study recommended that an educational program should be conducted to improve knowledge, practice, and self efficacy for patients with COPD. Aim :of the present study was to assess knowledge, practice, and self efficacy for patients with COPD. Materials and Methods: A descriptive research design was used in the study. A convenience sample consisted of all available patients (100 ) patients with COPD at the outpatient clinic of Respiratory Medicine, Mansoura University Hospital. Three tools were used to collect data.   Results: the present study concluded that 93%, 86%, and 96.0% of the studied subjects had unsatisfied knowledge, poor practice, and low self efficacy scores about COPD respectively. There was significant statistical relation between patients' occupation and their total knowledge scores, and a significant statistical relation between patients' occupation and their total practice scores. However there was no significant statistical relation between patients' knowledge, practice and their self efficacy. The study recommended that an educational program should be conducted to improve knowledge, practice, and self efficacy for patient with COPD. Recommendation: The study recommended that an educational program should be conducted to improve knowledge, practice, and self efficacy for patients with COPD.