e18555 Background: Philadelphia-chromosome negative myeloproliferative neoplasms (MPN) are a group of hematologic malignancies with known complications of hemorrhage and thrombosis. Age and a previous history of thrombosis are well-documented risk factors for future vascular events. Variations in the rates of these complications among ethnicities and sexes have not been extensively explored. Methods: Our retrospective analysis included 301 adult patients with a diagnosis of MPN without a history of thrombosis or hemorrhagic event seen at the Indiana University Simon Cancer Center between 1992 and 2019. Relationships between ethno-racial backgrounds and vascular complications and disease outcomes were evaluated using multivariate logistic regression analysis and Cox regression models. Results: Two hundred seventy-one patients (90.0%) were Caucasian and 30 patients (10.0%) were non-Caucasian. Non-Caucasian patients were comprised of African America, Asian, and Middle Eastern ethnicities. Median age at diagnosis was 56 years, and 43.9% were male. No association was found between the incidence of thrombotic complications and ethnicity using the log-rank test ( p 0.68). The incidence of hemorrhagic events was significantly increased in non-Caucasian patients (OR = 4.33; 95% CI [1.15 – 16.36], p 0.03). Patients with higher hemoglobin concentration at diagnosis were at a significantly lower risk of bleeding complications (OR = 0.79; 95% CI [0.65 – 0.95], p 0.01). Non-Caucasian patients were at 2.98 times (95% CI [1.19 – 7.44], p 0.02) higher risk when vascular complications were pooled together. Our models also showed that male sex (OR = 0.14; 95% CI [.02 – .98], p 0.048) and a higher platelet count at the time of diagnosis (OR = 0.99; 95% CI [.993 –.999], p 0.03) had a marginally significant association with decreased rate of progression to acute myeloid leukemia. Conclusions: This study suggests that in patients without a history of thrombosis or bleeding, non-Caucasian ethnicity was associated with an increased adjusted risk of hemorrhagic complications in patients with MPN. This observation may inform future studies to further characterize those disparities in outcomes at the genetic or socioeconomic level.