The article deals with the ninety years of history of the Czechoslovak (Czech) Society of Otolaryngology (Czech Society of Otorhinolaryngology - Head and Neck Surgery) since the day of origin (15th May, 1921). Briefly, the development, organization and scientific-professional activities in the time periods marked by political events are outlined, specifically the years 1921-1939, 1939-1945, 1945-1969, 1969-1989, 1989-1993 a 1993-2011, respectively.