This invention provides for novel antiparasitic and pesticidal derivatives of avermectin and milbemycin compounds in which two avermectin or milbemycin members are linked together by a chemical linker. The resulting compounds may be used in veterinary compositions which are used in treating, controlling and preventing of endo- and ectoparasite infections and infestations in animals or for combating pests in plants or plant propagation material.