As part of a study of two therapeutic protocols initiated in 1982 and 1985, respectively, for localized (n = 134) and disseminated (n = 76) large cell lymphomas, histologic type was determined for each patient by several pathologists using the Kiel classification for morphologic features and the international working formulation for protocol assignment and multifactorial statistical analysis. Therapeutic results in the two hundred and ten cases were correlated with a number of prognostic factors including age, stage, tumor size, extranodal disease, and clinical or biological markers for disease activity such as the LDH level. The previously reported influence of histologic subgroup on prognosis was not found with these highly effective protocols, whether histologic type was considered alone or in combination with other prognostic factors. The only consistent finding was that anaplastic large cell lymphomas, despite their aggressive features, were most likely to have a favorable outcome.