Clinical features and conventional and molecular diagnostic procedures have been investigated and evaluated for the infection caused by the lungworm Aelurostrongylus abstrusus (Nematoda, Strongylida). Individual fecal samples from all cats living in a colony with suspected lungworm infection underwent coprological flotation with sugar and zinc sulfate solution and the Baermann migration method. Also, pharyngeal swabs collected for each animal were subjected to a diagnostic nested PCR assay specific for a region internal to the ribosomal Internal Transcribed Spacer 2 of A. abstrusus. Eighteen animals were positive at the Baermann method, while 12 and ten out of them were negative when feces were subjected to the flotation with sugar and zinc sulfate solution, respectively. The nested PCR assay yielded positive results when using the pharyngeal swabs from the 18 coprologically positive cats and from six more cats which were coprologically negative, thus indicating an overall infection rate of 24.4%. Twenty-two out of 24 infected cats showed clinical respiratory symptoms and the most common were general respiratory distress, cough, wheezing, sneezing, and nasal discharge. These results indicate that cat aelurostrongylosis is of clinical importance and, thus, needs to be included in differential diagnosis of feline respiratory diseases. The importance of the disease is discussed together with pros and cons of different conventional and innovative diagnostic approaches.