Seventeen neuroendocrine neoplasms of the larynx were examined for DNA ploidy. Twelve tumours were atypical carcinoids, four paragangliomas and one a small cell neuroendocrine carcinoma. Seven atypical carcinoids were aneuploid, one diploid and one tetraploid, with metastasis being aneuploid. In three cases only skin metastases were available for study, which were aneuploid. The small cell neuroendocrine carcinoma was aneuploid. Two of the paragangliomas were aneuploid and two diploid. Like other sites, neuroendocrine neoplasms of the larynx have a high rate of aneuploidy. Determination of DNA ploidy did not provide useful diagnostic or prognostic information.