Background: Thrombosis and bleeding are the most common complications which contribute to significant morbidity and mortality of myeloproliferative patients. This study aimed to find out the incidence of thrombotic and bleeding events during diagnosis and follow up among patients with myeloproliferative neoplasm. This might help in the early detection of thrombosis and bleeding and prevention of such complications for MPN patients. Methods: A systematic review and meta-analysis was conducted to assess the incidence of thrombosis and bleeding. Data extracted from the literatures in Google scholars, Mendeley, PubMed, and EMBASE databases. Studies that had thrombosis and/or bleeding reports with any types of myeloproliferative neoplasm were included in this study. We used random effect model to estimate the odd ratio, relative risk and risk difference with 95%CI of each studies and the pooled results based on Cochrane methods of Revman. A funnel plot and I2 test checked to see the publication bias and heterogeneity respectively. Results: Nineteen studies with 14706 participants that had fitted the inclusion criteria were included in the overall thrombosis study. Five studies (n=931) included for incidence thrombosis at diagnosis and follow up. The pooled overall frequency thrombosis was 18.6%. The pooled incidence of thrombosis at diagnosis was 26.5% and odds ratio (OR= 3.17,95%CI 0.96 to10.43); relative risk (RR= 2.07,95%CI 0.98 to 4.34); risk difference (RD=21%, 95%CI -0.05 to 0.48, high certainty). Thrombosis had significant differences during diagnosis and follow up. A history of thrombosis, age >60years, and smoking were some of the risk factors for thrombosis. Conclusions: Based on the findings, thrombosis and bleeding are the highest complications occurred among myeloproliferative neoplasm patients. This problem is also common both during diagnosis and follow up of MPN patients. Early detection and follow up is needed to prevent MPN complications. Keywords: Thrombosis, bleeding, MPN, diagnosis, follow up.