Leptospirosis is endemic in Switzerland affecting a broad range of hosts. The aim of this study was to estimate the exposure of cats to Leptospira in Switzerland. Plasma samples from 107 outdoor cats with an array of clinical problems were tested via microscopic agglutination test for the presence of anti-leptospiral antibodies against 12 serovars of 9 serogroups. Using a reciprocal cut-off titre of 1:100, an overall seroprevalence of 10.3% (95%CI 5.2-17.7) was observed. Seroreactivity against serovars Bratislava (n = 6), Australis (2), Pomona (3) and Copenhageni (1) was detected with reciprocal titres ranging from 1:100 to 1:800. The serologic status of the cats was independent of the disease group (p = 0.62). These results show that cats in Switzerland are commonly exposed to Leptospira and confirm the importance of serogroup Australis in this region.