Computer processing by 73 characteristics in the system "host-tumor" was performed for 322 patients operated on for renal carcinoma from 1976 to 1986. The automatic classification method or cluster-analysis allowed distribution of the patients into homogeneous preoperative and postoperative groups (classes) which differed by the mean of the signs in the classes, survival and response to treatment. The formulas have been derived that enable the clinicians to refer the patients to a certain prognostic group without using a computer. This suggests more grounded examinations and treatment policy.