OBJECTIVE Treatment for high rectal cancers, particularly the value of preoperative treatment, is controversial. In our previous study, downstaging by preoperative chemoradiation resulted in improved outcomes. The aim of the present study was to identify prognostic factors to predict which patients will achieve downstaging and may benefit from preoperative treatment. METHODS In 54 patients with locally advanced non-metastatic high rectal cancer, 8 factors were evaluated for downstaging by preoperative chemoradiation including age, gender, carcinoembryonic antigen level, performance status, T-/N-category, UICC-stage (Union for International Cancer Control) and histological grade. Downstaging was defined as decrease by at least one UICC-stage. RESULTS Downstaging was achieved in 36 patients (67%). Patients at UICC-stage III showed a trend for downstaging. CONCLUSIONS The majority of patients with UICC-stage III tumors were downstaged and appear to benefit from preoperative chemoradiation. In general, the potential value of preoperative treatment for high rectal cancers needs further investigation.