What makes pet owners chose one veterinary practice and not another? This survey was performed to gain insight into what factors influence new clients' choice of veterinary practice, and consequently the most effective way to promote veterinary practices. To this end, a questionnaire was completed by 129 pet owners who became new clients of one of eight selected veterinary practices in January 2005 or later. All selected practices are members of the Dierenartsen Dienstgroep Domstad, Utrecht, The Netherlands. This survey showed word-of-mouth referral to be the most effective way to increase a practice client base: 32.8% of all respondents first heard of their practice of choice through a fellow pet owner. Other pet owners first 'heard' of their practice by passing the practice (17.2%), seeing an advertisement in the Yellow Pages (14.1%), visiting the veterinary practice website (13.3%), and looking in the phone book (10.9%). These information sources should be considered for promotional activities. However this is not the case for advertisements in newspapers or magazines: none of the respondents became acquainted with the practice through these media. Respondents primarily based their choice on personnel and product (the total package of services and its quality) and less on location, but many prospective clients also based their choice on promotional activities and prices. Because pet owners apparently take so many aspects into consideration when choosing a veterinary practice, the marketing orientation (focusing on the client with her/his wishes and problems) is crucial.