Toxocara canis and T. cati are not only ubiquitously distributed parasites of dogs, foxes and cats, but may also infest humans, causing a great variety of symptoms and sometimes also severe diseases: the visceral larva migrans syndrome, the ocular larva migrans syndrome, covert toxocarosis, common toxocarosis, neurological toxocarosis, and some other clinical pictures (asthma bronchiale, epilepsy, rheumatoid arthritis) are considered to be induced by Toxocara species. Both Toxocara species are also widely distributed in Austrian dog, fox and cat populations; seroepidemiological studies carried out in Austria revealed seroprevalence rates of 3.7% among the normal human population and up to 44% among persons particularly exposed to those parasites (i.e. veterinarians, farmers). Although many Toxocara infestations do not cause severe clinical manifestations, a few dozens of toxocarosis patients have been registered every year during the last years; in reality, however, we have to assume that several hundreds of patients suffer from toxocarosis. This paper tries to give a synoptic overview of the nosology of this (still) largely almost unknown helminthozoonosis, moreover it summarizes the most important epidemiologic parameters, and presents the diagnostic and therapeutic possibilities available today.