Objective:To report our experience with essential thrombocythemia complicating pregnancy.Methods:Over a 5‐year period, we studied 21 women of reproductive age affected by essential thrombocythemia. Diagnoses were based on previously published Polycythemia Vera Study Group criteria.Results:Five of our 21 patients became pregnant (total six pregnancies). All pregnancies were carried to term, with uncomplicated deliveries of normally formed infants. No thrombotic or hemorrhagic complications were encountered.Conclusion:Normal pregnancy and delivery is readily possible in patients with essential thrombocythemia.(Obstet Gynecol 1994;83:915‐7)