Ulcerative colitis is a chronic inflammatory disease affecting the colon, and its incidence is rising worldwide. The pathogenesis is multifactorial, involving genetic predisposition, epithelial barrier defects, and environmental factors. Aim: The aim was to evaluate the effect of Life style Modification on Patients with Ulcerative Colitis.. Setting sample: A purposive sample, A quasi-experimental (pretest posttest) research design was adopted for the current study. Fifty-seven patients with ulcerative colitis were enrolled in this study in gastrointestinal out-patient clinic at Kafre El sheik University Hospital. Tools: Structured patient interview questionnaire and Healthy lifestyle questionnaire tools were used to collect the data. Results: The study results revealed that (56.1 %) of the study participant were male whereas (43.8%) were female. The results revealed that total knowledge scores of patients' post-interventions were improved than that of their pre-scores, in addition to increase the total score of healthy lifestyle adherence after the study interventions and follow-up compared to pre intervention with highly statistically significant differences between them at p < 0.001. Conclusion: Lifestyle modifications can be effective in improving selected outcomes for patients with ulcerative colitis. Recommendations: Replication of the study on larger probability sample selected from different geographical areas in Egypt is recommended to more generalizable data.