Myeloproliferative neoplasms (MPNs) are a group of diseases that cause myeloid hematopoietic cells to over-proliferate. Epidemiological and familial studies suggest that genetic factors contribute to the risk of developing MPN, but the genetic susceptibility of MPN is still not well known. Indeed, only few loci are known to have a clear role in the predisposition to this disease. Some studies reported a diagnosis of MPNs and multiple myeloma (MM) in the same patients, but the biological causes are still unclear. We tested the hypothesis that the two diseases share at least partly the same genetic risk loci. In the context of a European multi-center study with 460 cases and 880 controls, we analyzed the effect of the known MM risk loci, individually and in a polygenic risk score (PRS). The most significant result was obtained among patients with chronic myeloid leukemia (CML) for PS0RS1C1-rs2285803, which showed to be associated with an increased risk (OR = 3.28, 95% C.I. 1.79-6.02, P = 0.00012, P = 0.00276 when taking into account multiple testing). Additionally, the PRS showed an association with MPN risk when comparing the last with the first quartile of the PRS (OR = 2.39, 95% C.I. 1.64-3.48, P = 5.98×10 ). In conclusion, our results suggest a potential common genetic background between MPN and MM, which needs to be further investigated. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.