This research utilizes the Model for Marketing in Small Professional Service Firms, based on Carson's Model for the Development of Small Firm Marketing, to examine the marketing of Physician Services in Puerto Rico. To achieve its objectives, a combination of quantitative(survey) and qualitative (cases) research is used. From the literature a series of statements is generated to form hypotheses that are tested utilizing the results of a questionnaire survey of 105 physicians in Puerto Rico. The results suggest a possible change of attitude of service providers towards marketing and its use. They reveal that physicians in Puerto Rico are in agreement with the marketing concept but most do not adopt "traditional" techniques of marketing- preferring to focus on the physician/patient relationship. Analysis of eight cases demonstrates the importance of this relationship and suggests that though is seen as important in attracting and retaining patients, most physicians do not see this as marketing, which is perceived to be mostly "advertising" and "selling." Many are cautious not to "commercialise" their practice and any differences in their behaviour can be explained by the way they believe the physician/patient relationship is best enhanced. The research proposes a Model for Marketing Solo Professional Service Firms that depicts the_ relation between the changes, over time, in the personal life cycle of the service provider/owner manager and the stages in the life cycle of the business practice. The model suggests that throughout there is a need to focus on one aspect of marketing for the practice, which may change over time, and that the elements determining the marketing activities at a particular time, how they are undertaken and why they are utilised, are constantly evolving. Thus the marketing practices of small professional firms appear to be contingent on both the external and internal environment of the practice.