BACKGROUND AND AIMS: Over 10% of patients with Crohn's disease require permanent ileostomy. We aimed to summarize the existing data on diagnosis, definitions of recurrence, and management of Crohn's disease patients with permanent ileostomy. METHODS: MEDLINE, Embase, and CENTRAL databases were searched from inception to February 6, 2024. Randomized controlled trials, cohort and cross-sectional studies, and case series of more than five patients reporting on postoperative recurrence or the need for surgery in patients with Crohn's disease and permanent ileostomy were included. Search results were independently screened, and full text of all titles meeting eligibility criteria were obtained. Outcomes of interest included diagnostic techniques, recurrence definitions, and management approaches. We estimated pooled rates [with 95% confidence interval] of recurrence. RESULTS: Thirty cohort studies including 2,055 Crohn's patients with permanent ileostomy were included (53% female, median age at time of ileostomy creation 32 years, most common reason for ileostomy was refractory disease). The postoperative recurrence rate was 27% (95% CI, 21.3-33.3, 26 studies, 451/1805 patients). Modalities for diagnosis of Crohn's disease recurrence were symptoms (15 studies), endoscopy (4 studies), histology from endoscopic biopsies (2 studies), imaging (5 studies) and surgery (22 studies). The reported definitions of recurrence for each modality were heterogeneous. CONCLUSIONS: There is a lack of standardized monitoring tools and criteria for diagnosing recurrence in patients with Crohn's disease and permanent ileostomy. The results of this systematic review will form the basis of a global expert recommendation exercise focused on developing management standards and trial endpoints for this condition.