Extreme thrombocytosis is a frequent feature in myeloproliferative disorders which can predispose a person to thrombotic complications. As opposed to other myeloproliferative disorders, symptomatic thrombocytosis is rare in chronic myeloid leukemia. We describe a second case report of chronic myeloid leukemia (Ph chromosome positive) in a patient in chronic phase on hydroxyurea who presented with sudden onset digital cyanosis of the left hand, giddiness, headache and malaise due to extreme thrombocytosis. A 67% global reduction in the platelet count from 1553 x 10(9)/L to 513 x 10(9)/L after two therapeutic plateletpheresis procedures was seen. There was simultaneous improvement in all symptoms except cyanosis on the tip of the middle finger that progressed to dry gangrene. Dramatic reduction in the platelet count and ablation of symptoms by therapeutic plateletpheresis is an effective therapy and should begin as soon as possible.