The report deals with the data on 133 patients with primary tumors of the vagina treated with both combined (tele- and contact gamma therapy) and contact treatment using low, medium and high dosage. The following radiobiological models were used for evaluating and comparing responses of normal tissue: time-dose fractionation, cumulative radiation effect and linear-square law model referred to as the "extrapolation-related dose of response". The results suggest that combined radiotherapy using high-dose contact treatment be recommended for localized stage I-II tumors while cases of stage III tumor should receive only combined radiotherapy provided brachitherapy uses modern radiation equipment which will assure a minimal gap between the nominal and actual characteristics of irradiation.