Background: The frequency of endoscopically apparent gastrointestinal tract (GI) involvement in patients with mantle cell lymphoma (MCL) at diagnosis is thought to be in the range of 30%. While reports on GI involvement in MCL patients exist, most series lack a strict GI assessment due to the often asymptomatic nature of GI involvement. Owing to the standardized staging routine at our institution including GI assessment at diagnosis, we have analyzed the rate and prognostic impact of GI involvement in MCL. Methods: In this retrospective single-center evaluation, we have investigated GI involvement in 85 consecutive patients with MCL. All data were collected from clinical records. Results: MCL with and without endoscopically detectable GI involvement was reported in 29 (34%) patients and 56 patients (66%), respectively. The colon was involved in 21 (72%) and the stomach in 8 (28%). Eight of 29 patients (28%) had symptomatic GI involvement, and the primary diagnosis had been established in the GI tract in 3/29 (10%) of our patients. No statistical differences could be observed between both groups in terms of gender (p = 0.474), Eastern Cooperative Oncology Group (0.428), and MCL international prognostic index (0.543). Overall survival was longer in patients with GI involvement (116.0 vs. 74 months), but not statistically significant (p = 0.825). Conclusions: In our single center cohort, we did not find a clinical impact of GI involvement on the clinical course of MCL and no GI complications occurred during chemotherapy in these patients. As most patients were also asymptomatic, these data argue against a routine GI assessment in patients diagnosed with MCL.