Background: Evaluation of tolerance and efficacy of two schemes of neoadjuvant treatment in patients with unresectable rectal cancer: radiochemotherapy and radiotherapy, including conventional and accelerated hyperfractionation. Methods: 145 patients (pts) with unresectable, locally advanced rectal cancer. Schemes used: radiotherapy (RT) in 73 (50%) or radiochemotherapy (CRT) in 72 (50%). In RT group conventional fractionation (CFRT) and hyperfractionated accelerated radiotherapy (HART). In CRT 54 Gy in 1.8 Gy fractions was given with two cycles of 5 Fu-LV chemotherapy in three or five day cycles. Results: Objective response (OR) in RT and CRT group was 60% versus 75%. Resection rate (RR) in RT and CRT: 37% versus 65%. Tumor mobility and laparotomy-based unresectability were significant factors for OR. Performance status, tumor mobility, neoadjuvant treatment method were significant for RR. Five-year LC in CRT versus RT: 68% versus 37%. Five-year OS: 52% versus 27%. CRT was independent positive prognostic factor for resection rate, local control. Tumor volume did not reach significance for any of the end points. Lenght of chemotherapy cycles (three or five days) did not reach significance for any of the endpoints. Toxicity was acceptable in both groups. CRT had best outcome in LC: 68% versus 42% in HART; and 25% in CFRT. Five-year OS was much better in CRT than in CFRT: 52% versus 17%. Conclusions: The results of treatment depend on performance status, patients age, tumor mobility and unresectability based on earlier laparotomy. The lack of influence of the tumor volume on all endpoints indicates the need for radical neoadjuvant treatment independently of tumor volume and underlines the key role of a proper surgical treatment. In patients not suitable for CRT, HART is optimal strategy for its better efficacy than CFRT.