Herein we describe the case of a patient with focal segmental glomerulosclerosis (FSGS) following polycythemia vera (PV) on whom hemodialysis was started 7 years later. A 66-year-old woman who had been treated for PV with hydroxyurea and phlebotomy for three years was referred to our hospital because of nephrotic syndrome. Renal biopsy performed at her local hospital revealed FSGS. Although she had received prednisolone at an initial dose of 45 mg/day, no significant improvement of proteinuria was achieved. The dose of prednisolone was tapered because the second renal biopsy revealed sclerosing glomerulopathy. We considered that FSGS was associated with PV because renal hemodynamic alterations in PV could result in FSGS as in any other secondary FSGS and there was no proteinuria at the initial detection of PV. On January 29, 1999, she developed massive proteinuria (9.6 g/day) and the findings of the third renal biopsy worsened in comparison with that of the first renal biopsy. Thereafter, hydroxyurea or ranimustine was used in treating PV at an outpatient clinic. However severe thrombocytosis was difficult to control, and progressive renal dysfunction finally necessitated hemodialysis on January 18, 2005. In conclusion, physicians should be aware of the risk of progressive renal failure in patients with FSGS following PV, particularly in patients with persistent thrombocytosis.