The monograph reviews viruses, bacteria, microfungi and protozoa pathogenic to homeotherm vertebrates (including humans) associated with birds of the family Laridae (larids, for short). The survey also presents a review of larid microbial diseases worldwide: a total of 569 determined microbial morbidity and mortality events in larids have been reported. The dominating disease is avian botulism (in fact, microbial toxicosis) representing 38% of all recorded microbial disease events. Additional relatively frequent and important diseases in larids are salmonellosis (10% of all recorded microbial events), aspergillosis (9%), avian cholera (9%), Newcastle disease (5%) and ornithosis (5%), while other microbial diseases have occurred in < 5% of the reported events: West Nile virus disease, haemosporidiosis, avian influenza, avian tuberculosis, toxoplasmosis, coccidiosis, avian pox, tick-borne virus diseases, circovirus infection, avian papilloma, erysipelas, candidosis, staphylococcosis, sarcosporidiosis, cryptosporidiosis, necrotic clostridial enteritis, colibacillosis, babesiosis, calicivirus and avian bornavirus infections. However, many observations indicate that some microbial diseases of larids have remained unidentified and additional investigations about infectious morbidity and mortality in them is warranted.