Although neutron irradiation for prostate cancer has been associated with significant morbidity, pilot data in patients with early stage disease suggested that conformal neutron and photon irradiation was well tolerated without severe complications. A self-assessment questionnaire was mailed to the first 83 patients treated with conformal neutron and photon irradiation to objectively evaluate the impact on quality of life of this regimen. In total, 75 patients (90%) returned the completed questionnaire. These patients had received either 9 neutron Gy (N Gy) plus 38 photon Gy (50 patients) or 10 N Gy plus 38 photon Gy (33 patients) for stage T1/T2 N0 M0 prostate cancer (Gleason score ั7). The irradiated volume included the prostate and seminal vesicles with a 1.5 cm margin. Neutrons were delivered as a boost to the prostate only with a non-axial four field beam arrangement. Approximately 50% of the dose to the prostate was from neutron irradiation. Follow-up ranged from 6 to 25 months (median 13 months). The questionnaire used was a validated quality of life instrument used previously in patients treated with surgery or radiation. Prior to irradiation, 29% of patients reported urinary symptoms and 11% had prostate surgery (TURP). At follow-up, 23% reported persistent urinary symptoms. Of these, 21% dripped a few drops of urine, 3% used pads but none leaked >1 tablespoon/day. One patient underwent surgery to dilate a urethral stricture. Although 55% of patients had gastrointestinal symptoms during radiation therapy, only 26% had persistent symptoms at the time of questioning. These included minor rectal bleeding in 20% and significant hematochezia in 3%. Of the 85% of patients able to obtain full or partial erections prior to irradiation, 87% maintained their potency. Fifteen percent sought treatment for impotence. Overall, at last follow-up, 84% felt little or no physical discomfort, 91% were very satisfied with their treatment, and 97% would choose radiation therapy again. This patient self-assessment questionnaire confirmed that this regimen of conformal neutron and photon irradiation resulted in levels of chronic toxicity acceptable to the patient.