Self-management program is vital for supporting, educating and improving patients’ self-efficacy with stoma. Aim of the study: was evaluated the effect of a self-care management program on self-efficacy of patients with colostomy. Hypothesis: self-management program had a positive effect on self-efficacy among patients with colostomy. Design: Quasi-experimental research design was used. Setting: The study was conducted at Benha Teaching Hospital, oncology unit in the general surgical department and outpatient Clinic. Subjects: A purposive sample of 30 patients from both genders. Tools: four tools were designed to collect data; stoma- related knowledge sheet, which was developed to assess Patients` knowledge about colostomy care. Self-care performance checklist, Ostomy Skin Tool to assess the extent and severity of peristomal skin complications and Stoma care self-Efficacy Scale. Results: mean score of age was 55.7± 8.56, 63.3% was mal, 80% was married, and 73.3% had bowel cancer. Mean score of total knowledge pre-program was 10.700±1.022, which increased to 24.70± 1.441 post program. 66.7% of patients had severe peristomal skin complications preprogram which decreased to 60% post program, while in follow up 56.7% of patients had mild peristomal skin complications. Related to stoma care self-efficacy there was statistical significant differences between three phases (p=.000). Conclusion: there was highly significant statistically improvement in all items of knowledge, practices and self-efficacy pre/post program of self-care management regarding colostomy patients. Recommendations: assessment of patients’ self-care performance during first six months after operation considered as evidence to his educational needs and concern.