To our knowledge only a few defined studies have been carried out on laryngeal cysts. These cysts represent a mixed group of benign laryngeal lesions that can cause diagnostic and therapeutic difficulties. The aim of this study was to characterize their histological structure and localizations in the larynx as well as to discuss theories about their genesis. Between 1973 and 1996, 342 laryngeal cysts were treated at Phillips University of Marburg, while from 1990 to 1996, 74 were treated at Justus Liebig University of Giessen. In all, 416 laryngeal cysts were treated by endolaryngeal microsurgery. All clinical charts were reviewed retrospectively and surgical specimens examined histomorphologically. Findings showed that 58.2% of the laryngeal cysts were located in the glottic area and 18.3% in the ventricular folds. The remainder were located on the aryepiglottic fold (2.2%) and interarythenoid region (0.7%). Two congenital cysts were also treated. Approximately 56% of the laryngeal cysts were lined by squamous cell epithelium, 37% by respiratory epithelium and 7% by oncocytic epithelium. In general, the laryngeal cysts were found to be a collection of inhomogenous lesions from different histogenetic origins with diverse symptoms related to their site and size. On the basis of our investigations, a new classification was established concerning the genesis and development of laryngeal cysts by subdividing cysts into congenital cysts, retention cysts, and inclusion cysts.