Objective:To analyze the clinical features and prognosis of lymphoma patients with monoclonal immunoglobulin (McIg).Methods:The data of 14 patients who were pathologically diagnosed as lymphoma and with McIg in the First Affiliated Hospital of Fujian Medical University from January 2014 to January 2019 were retrospective analyzed. At the same time, 40 lymphoma patients without McIg were sellected as controls. The patients'age, gender, international prognostic index (IPI) score, B symptoms, tumor cell source and Ki-67 index were analyzed by prognostic single factor analysis. Kaplan-Meier method was used for survival analysis, and the overall survival (OS) and progression-free survival (PFS) were compared between the two groups.Results:Among 14 lymphoma patients with McIg, 6 were males and 8 were females. The median age of onset was 63 years (42-78 years). There were 13 cases of clinical stage Ⅲ-Ⅳ, and 12 cases of extranodal disease. The most common type was IgM-κ. The results of univariate analysis showed that IPI score≥3 points and elevated D-dimer level were related to poor prognosis (both P < 0.05). At the end of follow-up, the median OS time of lymphoma patients with McIg had not reached, the 2-year OS rate was 64.3%, and the median PFS time was 16 months; the median OS time of lymphoma patients without McIg had not reached, the 2-year OS rate was 90.8%, and the median PFS time was 37 months; the difference of OS between the two groups was statistically significant ( P = 0.040). Conclusions:Most lymphoma patients with McIg have extranodal involvement, the clinical stage is more inclined to stage Ⅲ-Ⅳ, IPI score ≥3 points and elevated D-dimer level are poor prognostic factors. The secretion of McIg is an important factor for the poor prognosis of patients with lymphoma.