All serum protein electrophoresis (SPE) results obtained between 2002 and 2009 from clinical cases presented to the University of Bristol Feline Centre were examined retrospectively. One hundred and fifty-five results met the inclusion criteria. Signalment and final diagnoses were obtained from the case records. Clinical cases were classified as having normal or abnormal SPE results by comparison to reference intervals for SPE created using 77 clinically normal cats. Abnormal results were then further divided according to the specific SPE abnormality. Cases were also categorised, according to the final diagnosis, using the DAMNITV classification system. Of the 155 cases, 136 (87.7%) had abnormal SPE results, most commonly due to a polyclonal increase in gamma globulins. A monoclonal gammopathy occurred in four cats; one with feline infectious peritonitis (FIP), one with lymphoma and two cases of splenic plasmacytoma (one suspected, one confirmed). The most common DAMNITV classification associated with SPE abnormalities was infectious/inflammatory disease (80/136; 58.8%), including 39 cats diagnosed with FIP.