Three hundred and forty-six serum samples taken between 1998 and 2000 from urban stray cats in the city of Ghent were tested for antibodies to Toxoplasma gondii and feline immunodeficiency virus (FIV), and antigens of feline leukemia virus (FeLV). Of these 346 samples, 243 (70.2 per cent) were seropositive for T gondii. Thirty-nine cats (1 1.3 per cent) had antibodies againSt Flv and 13 (3.8 per cent) had circulating antigens Of FeLv. Fewer of the female cats had FIV and heavier cats had a higher seroprevalence Of FIV. Exact logistic regression showed that cats that were infected with FIV were more likely to be infected with T gondii (P=0.04), and the cats with Fivl had a higher titre of T gondii antibodies than Fill-negative animals. However, FeLV was not associated with either T gondii or FIV.