This study was aimed at evaluating the efficacy of beta-carotene in improving survival (S) and in disease-free survival (DFS) and reducing the incidence of second primary tumors (SPT) in patients with a radically treated stage I-II squamous head and neck tumors. Eligible patients were randomly allocated to receive beta-carotene (n=104) or no treatment (n=110). beta-carotene was administered at the dose of 75 mg/day for 3-month cycles within one month intercycle intervals for a 3-year period. The 3-year compliance to the beta-carotene was 68.7%. Only eight patients reported drug-related toxicity (7.8%). The median follow-up of all patients was 59 months. The median follow-up was 61 months (range 1-116 months) in the beta-carotene and 58 months (1-123 months) in the control group. The 10-year DFS was 75.7% for the patients in the beta-carotene and 74.3% for those in the control group (P=0.56). The 10-year S was 85.9% in the beta-carotene group and 80.9% in the control group (P=0.20). beta-carotene supplementation had no significant effect on the incidence of second primary tumors (RR=0.99; 95% C.I. 0.28-3.44). A statistically non-significant 40% reduction in the risk of death among subjects assigned to the beta-carotene compared to the controls was observed (RR=0.60; 95% C.I. 0.26-1.38). No increase in the death from cardiovascular diseases was observed among patients treated with beta-carotene. Our results might support the hypothesis that an adequate beta-carotene treatment could be potentially associated with a decreased risk of death in these patients.