Chondroblastoma is a rare benign tumor occurring in adolescence and young adulthood, almost always involving the epiphysis of long bones. A 24-year-old man presented with a discrete soft-tissue lesion penetrating the cortex of the right distal femoral metadiaphyseal region. Biopsy revealed a chondroblastoma, and the patient subsequently underwent a total curettage of the lesion with cancellous bone graft from the iliac crest.