A multiparameter analysis of immune function was done on patients with squamous cell carcinoma of the uterine cervix to look for any variable(s) that could be correlated with the clinical stage of the disease. Five immunological variables, viz., CD4+ lymphocytes, CD4/CD8 ratio, natural killer cells, concanavalin A-induced suppressor index, and circulating immune complexes, were found to consistently vary with tumor load. When these variables were subjected to a multiple regression and multivariate analysis, an equation for a diagnostic index curve was derived. Application of this equation led to an immunological staging system which could be used as an excellent prognostic indicator. The immunological staging system showed that patients classified into a particular clinical (FIGO) stage behaved in a heterogeneous way immunologically and that patients developing recurrent disease could easily be identified from those remaining disease free, even before treatment. Subsequent follow-up of these patients further confirmed this observation, with the recurrent disease group easily identifiable. These results point out the immense potential of such a staging system and the importance of immunological evaluation in the preliminary management of patients with malignant cervical neoplasia.