This study explored the efficacy of intravenous immunoglobulin (IVIG) prophylaxis in reducing infection‐related hospitalizations (IRHs) in MM patients. This was a retrospective study of MM patients who received IVIG at Taussig Cancer Center between July 2009 and July 2021. The primary endpoint was rate of IRHs per patient‐year on‐IVIG versus off‐IVIG. 108 patients were included. There was a significant difference in the primary endpoint of rate of IRHs per patient‐year on‐IVIG versus off‐IVIG in the overall study population (0.81 vs. 1.08; Mean Difference [MD], −0.27; 95% Confidence Interval [CI], −0.57 to 0.03; p value [P] = 0.04). The subgroup of patients with a 1‐year period of continuous IVIG (49, 45.3%), the subgroup with standard‐risk cytogenetics (54, 50.0%) and the subgroup with 2 or more IRHs (67, 62.0%) all showed a significant reduction in IRHs while on‐IVIG versus off‐IVIG (0.48 vs. 0.78; MD, −0.30; 95% CI, −0.59 to 0.002; p = 0.03) and (0.65 vs. 1.01; MD, −0.36; 95% CI, −0.71 to −0.01; p = 0.02) and (1.04 vs. 1.43; MD, −0.39; 95% CI, −0.82 to 0.05; p = 0.04) respectively. IVIG showed significant benefit in reducing IRHs in the overall population and in multiple subgroups.