Pet cats live in close proximity with their owners and are considered a potential source of Toxoplasmagondii infection for humans. Four hundred and ten sera of healthy pet cats originating from different partsof Belgium were examined. The age of the cats varied from 3 months to 8 years. Nearly 27% of the cats testedpositive for Toxoplasma IgG and/or IgM antibodies. Toxoplasma seroprevalence was lowest in Flanders(20.4%), followed by Brussels (30.9%) and Wallonia (35.0%). Seroprevalence increased with age: from merely2% below 12 months of age, up to 47% at 7 years of age. Infection peaks were observed in the age group of12-23 months (17.6% increase) and, remarkably, also in the age group of 6 years (14.0% increase).The study suggests an overall chance of 5.5% for a seronegative cat to become infected within the next year.The risk of transmission of toxoplasmosis to the cat’s owner is discussed.