Deyrolle is the name of a well-known family of 19th century naturalists who are familiar to us, but their activities and their contributions to the natural sciences have never been the subject of a study. And yet, over three generations, the members of this family give us a broad view of the naturalist milieu during the 19th century. We will first tell about Jean-Baptiste Deyrolle and his three sons : Achille, Narcisse and Henri, then Achille’s three children : Hortense, Émile and Théophile. It is sometimes difficult to distinguish the activities of each of them as they are complementary. Alternately explorers, naturalist merchants, collectors, scholars, publishers, illustrators, popularizers, they were influential players in the naturalist milieu in Paris of the 19th century. Four of them went to explore distant regions (southern Brazil, Gabon, Caucasus and eastern Anatolia) still poorly known to Europeans, with the aim of inventorying the living world, and collecting specimens of fauna and flora. They were active in various learned naturalist societies and contributed to attempts to acclimatize new plant and animal species in France. Through their taxidermy activities and preparations of exotic animals, they have provided thousands of specimens from the whole world to the European museums to be discovered by their visitor. They were recognized entomologists, some hunted, others collected, sold, exchanged, appraised, studied, illustrated, colored thousands of insects. They played a major role in assembling patrimonial entomological collections and left a strong imprint in entomological taxonomy. They were also interested in applied entomology and were involved in major national causes such as the fight against the Colorado potato beetle which caused severe damage in its cultivation and the introduction of new species of silkworms to save sericulture. They dominated the Parisian market for everything related to Natural History, they worked to supply scientific institutions with diverse and rare specimens, to develop tools and products to meet the needs of amateur and professional collectors. They even invested themselves in the fashion of their time by making feather ornaments for hats and insect jewelry. They have been laureates of major international events, in particular the Universal Exhibitions that have marked their century. By publishing magazines and popular works, by creating educational tables for schools, they initiated generations of schoolchildren to the knowledge of nature. In the service of science and education for nature, they have occupied a central rule in publishing natural sciences and in the dissemination of knowledge.