Chondroblastoma located in the femoral head is one of the locations accounting for frequent recurrence. One of the reasons for this is the difficulty in obtaining appropriate surgical access to it for adequate removal of tumors. The authors present and illustrate a trapdoor procedure for the surgical treatment of chodroblastoma in the epiphysis of the femoral head. The surgical approach was made over the great trochanter and a trochanteric osteotomy was performed. The capsulotomy was made anteriorly and posteriorly, and the hip was dislocated anteriorly. Using a scalpel and an osteotome, the edges of a trapdoor segment were sharply dissected and the rectangular segment was lifted back to reveal an underlying subchondral tumor. The tumor tissue was thoroughly curetted and autologous cancellous bone was grafted. The trapdoor was replaced without any additional fixation, and the femoral head was reduced. The patient recovered good hip function without pain, and showed no recurrence of chondroblastoma at 5 years after surgery. The trapdoor procedure enabled sufficient access to complete curettage and autologous cancellous bone grafting for the chondroblastoma of the femoral head. This procedure proved to be a useful surgical approach for the treatment of chodroblastoma in the epiphysis of the femoral head in this case.