AbstractIntroductionChlamydia felisis the main chlamydial pathogen of cats and is associated with conjunctivitis and respiratory disease. This study aimed to estimate the prevalence ofChlamydiaceaeandChlamydia felis, to explore risk factors and predictors (age, sex, breed, origin and ocular signs) for infection using logistic regression, and to appraise genetic diversityvia ompA sequencing and phylogenetic analysis.Material and MethodsConjunctival swabs from 156 cats were examined using real-time PCR assays forChlamydiaceaeandC. felis. Logistic regression and Kaplan–Meier analysis evaluated risk factors, and partialompA sequences were phylogenetically analysed.ResultsChlamydiaceaeDNA was detected in 7.7% (12/156) of cats and was identified asC. felis. Infections were mostly unilateral. Threshold cycle values varied widely, suggesting heterogeneous bacterial loads. Younger age was a significant risk factor, and the probability of infection decreased steadily with age. Ocular signs strongly predicted infection. British Shorthair/Longhair cats had more than threefold higher odds of infection than European Shorthair cats. Phylogenetic analysis ofompA showed very high genome conservation (99.7–100%), which was consistent with global data.ConclusionThis first molecular study ofC. felisin Poland in ten years demonstrates that infection mainly affects young, purebred cats with apparent conjunctivitis. The genetic stability ofompA supports the concept of a globally homogeneousC. felispopulation.