Ricardo Zariquiey Cenarro (1870–1943) and his son, Ricardo Zariquiey Álvarez (1897-1965), were paediatricians who devoted their free time to a shared passion, the study of deep hypogeal beetles (Coleoptera, Insecta) and decapods (Crustacea). Zariquiey Cenarro became fascinated by biospeleology – and cave-dwelling fauna in particular – in 1917 and later, with his son, developed a profound knowledge of cave-dwelling Coleoptera. Zariquiey Álvarez amassed an important collection of hypogeal Coleoptera, which was donated to the Natural Sciences Museum of Barcelona as a result of his friendship with Francesc Español, who at that time was the director of the Museum. This donation, along with Español’s own collection, became the basis of one of the best collections of hypogean Coleoptera fauna in Europe. Zariquiey Cenarro also undertook a study of crustaceans, which his son continued after his father’s death to become one of the most important carcinologists of the time. Zariquiey Álvarez created one of the best collections of Mediterranean decapods, composed of more than 20,000 specimens and 470 type specimens, which he donated to the old Instituto de Investigaciones Pesqueras, today known as the Institute of Marine Sciences in Barcelona (ICM-CSIC). His studies of decapods were completed with a posthumous work, Crustáceos Decápodos Ibéricos (1968), which is still one of the main reference works on Decapoda. This communication is a tribute to the scientific careers of these two eminent zoologists who bequeathed two important reference collections