Prognostic information is essential for the evaluation, judgement, and optimal treatment of malignant head and neck tumors. The prognostic significance of DNA flow cytometry has been investigated for many solid tumors, but few data have been accumulated for laryngeal cancer. Flow cytometry can be broadly defined as the objective measurement of specific cellular features of a sample in an automated fashion, as the sample moves passing a stationaly detector. Flow cytometric DNA analysis was performed in 29 patients treated in our hospital by total laryngectomy for laryngeal cancer between 1987 and 1990. Of 29 patients with primary carcinomas, 21 had glottic and 8 had supraglottic carcinomas. Ten out of 29 patients(35%) had diploid tumors and the remainders were non-diploid. Five out of 29 patients had high DNA amount(more than 30% of cells beyond the diploid peak) and 24 out of them had low DNA amount. Seventeen out of 29 patients had S-phase cells more than 10%. DNA ploidy did not correlate with nodal status, histologic grade or tumor stage. DNA amount and S-phase fraction did not correlate with clinical courses, either. Survival was not influenced by the DNA ploidy, DNA amount and S-phase fraction in total-or partial-laryngectomized patients. It is concluded that DNA flow cytometric analysis might not be a good prognostic indicator in laryngeal malignancy.