Aims The objective of this study was to investigate the incidence and clinical significance of lymphoma‐associated chromosomal translocations, particularly those involving the immunoglobulin heavy chain gene ( IGH ) locus, in patients with small‐bowel diffuse large B‐cell lymphoma ( DLBCL ). Methods and results Translocations involving IGH , bcl‐6 , MYC and bcl‐2 were investigated with interphase fluorescence in‐situ hybridization on paraffin‐embedded tissues in 35 patients with primary small‐bowel DLBCL , and the overall survival ( OS ) and progression‐free survival ( PFS ) rates were evaluated with the Kaplan–Meier method. Translocations involving IGH , bcl‐6 , MYC and bcl‐2 were detected in 23 (70%), 12 (36%), eight (24%) and six (18%) of 33 cases, respectively. The patients with IGH translocations showed less frequent relapse or progression of lymphoma (17%) than those without (60%, P = 0.034). Univariate analyses demonstrated that young age, a low international prognostic index, translocations involving IGH , extra copies of MALT 1 / bcl‐2 and bcl‐6 immunoexpression were significantly associated with better OS and PFS . Cox multivariate analysis revealed translocations involving IGH to constitute an independent prognostic factor for better PFS , but not better OS . Conclusions Translocations involving IGH are frequent in cases of small‐bowel DLBCL . These translocations may be predictive of a favourable clinical course.