Background: The patient's quality of life is significantly impacted by colostomy, which significantly modifies their image, personal sanitation, and excretory function. Additionally, it erodes their self-esteem and limits their ability to manage daily life. Aim: Assess the influence of self-care educational instructions on the quality of life of colostomy patients. Design: Quasi experimental research design was used. Setting: the study conducted at oncology hospital and surgical outpatients‘ clinic at Tanta University. Subjects: A Purposive sampling of 60 colostomy Patients. Tools: Four tools were used. Tool I: Colostomy Self-Care Knowledge Questionnaire. Tool II: Ostomy Self-Care Index Scale.Tool III: Observational Checklist for Colostomy Self
care Practices, Tool IV: Stoma Quality of Life Index Scale. Results: The main results revealed that were a highly statistical significant improvement in total self-care knowledge level (73.3%), total self-care practice (86.7%) and total score level of stoma quality of life (80%) of the study group post implementation of self-care educational instruction. Conclusion: Quality of life, post-self-care educational instructions, and colostomy self-care knowledge, practices, and OSCI were all significantly positively correlated (r.0.298, r.0.517, r.0.497) Recommendation: Replication of the study with larger sample in different settings is required for generalization of the results.