Karl Rost (active 1880–1919) was a Germanentomologist and insect dealer. From 1886 Rost was an insect dealer (Insekten-Händler) and professional insect collector in Berlin. He collected insects later offered for sale in Spain and Greece (annually 1887-1898). In 1899 he went on an expedition to Siberia and in 1900 -1901 collected in the Caucasus. In 1903 he went to Japan to collect insects for the Swiss collector George Meyer-Darcis (He went to Japan again in 1911) after two years in North-West India (1906 for Meyer-Darcis and 1907 for his dealership). Rost described many new species from these regions. Parts of his personal collection are in the Museum für Naturkunde in Berlin and other parts are in the Zoologisch Museum Amsterdam. The rest were privately sold, many to the dealership Staudinger - Bang-Haas.