To investigate relationships between declining owned-cat populations and cat-related clinical work and practice activities. Sydney practitioners were interviewed, and practice records were examined, from small animal veterinary practices (n = 56) in Sydney. Using data that covered a 4 year period, the age distribution of cats was examined and associated trends in cat-related clinical work were analysed. Important changes in the pet population attending veterinary practices were found, with 38.2% of respondents reporting a fall in cat desexings from 1996 to 2000. While economic impact could not be determined, the qualitative data demonstrated that the majority of practices in the survey were active in the promotion of cat ownership. The study provides a useful model for future investigations. To facilitate this process and to enhance principals' knowledge of their practice's population dynamics, we advocate a minimum standard of data collection that records week-by-week activities and the deaths of pets.