The pattern of relapse, treatment and final outcome of 235 patients with osteosarcoma of the extremity who relapsed after neoadjuvant treatments performed between 1986 and 1998 at a single institution is reported. The 235 relapses were treated by surgery, surgery plus second line chemotherapy, and only second line chemotherapy or radiotherapy. The 5-year post-relapse-event-free-survival (PREFS) was 27.6% and the post-relapse-overall-survival (PROS) 28.7%. All 69 patients who are presently alive and free of disease were treated by surgery, alone or combined with chemotherapy. None of patients treated only by chemotherapy or radiotherapy survived. We conclude that it is possible to obtain prolonged survival and cure in about 1/4 of relapsing osteosarcoma patients with aggressive treatments. The complete removal of the recurrence is essential for outcome, while the role of the association of second-line chemotherapy remains to be defined.