We have utilized the computerized data of a nationwide health plan to elucidate several epidemiologic aspects and risk factor of myelodysplastic syndromes (MDS) in Israel. The annual incidence rate (IR) of reported MDS was of 3.32 per 100,000. Among anemic patients aged 40+, the risk of reported MDS was 56.7 per 100,000. Only 44% of the reported MDS cases had an indication of bone marrow examination. In a multivariable model, older age, hemoglobin level <9g/dl, white blood cell count of less than 3500/mm(3), and platelet count of less than 100×10(9)/L were associated with a significantly higher risk of MDS. The mean lag period from the first demonstration of anemia to the final diagnosis of MDS was 3.5 years. Our study results could be helpful for improving the detection of patients with high MDS risk, therapeutic decision-making, and designing interventional trials in the future.