Using Mexico City as a case study, this research proposes an alternative framework for research which, rather than add to the dominant narrative that public relations should become a formalised and recognised profession, seeks to understand the make-up of public relations as an occupational culture. It explores the values and experiences relevant to practitioners and emphasises the need to recognise the role of practitioners as intermediaries in the development of society. In contrast to the prevalence of quasi-experimental methodology often adopted in public relations research, this thesis advances a subjective, cultural approach to public relations research and practice. This study is based on the premise that methodological approaches in public relations research need to be flexible enough so as not to suppress the new meaningful insights, which may emerge of practice in other parts of the world. The narrative advances an `in-awareness' cultural approach to public relations research, applying a social constructionism-inspired perspective to the study of public relations as an occupational culture in Mexico City. In-depth interviews were carried out in Spanish with 32 practitioners working in public and private sector organisations. This data was supported by general observation and follow-up participant observation, in order to explore the potential for practitioners as cultural intermediaries in the development of a culture in transition. The study focuses on the practitioner lifeworlds (or public relations practitioner culture - PRP) and considers the impact that their habitus, occupational identities, social networks and experiences have on the ways in which they communicate. Influences from the occupational structure and the socio-cultural structure of Mexico were also explored. The data was analysed by way of a `constant comparison' method in order to identify patterns within the culture. The findings are presented in the form of five semi-biographical composite narratives that bring out the contrasting ways of seeing and acting: the `Young Public Relations Executive Experience', the `Old School Experience', the `Agency Director Experience', the `Inhouse Practitioner Experience' and the `Social Communicator experience'. The relationships between these patterns were then interpreted by way of analytic generalisation. Three core themes emerged: `Occupational Identity', `Interpersonal Communication and Networks', and `Ethics', each of which were grounded in practitioners' experiences of Mexican culture. The findings suggest that public relations in Mexico City might be regarded as an occupational ethos of relaciones humanas, a Spanish term to mean human-centred approach. This ethos would place value on human and trusted communication manifested in an authentic occupational `character' in and formal and informal interpersonal communicative practices. Amalgamating these findings with broader sociological and community relations theory and within the context of wider globalisation theory, a reconceptualisation of community relations was developed in order to explain the potential for public relations practitioners as cultural intermediaries in Mexico City. This thesis suggests that this potential might be at a personal, grass-roots level. By communicating interpersonally, practitioners would be able to communicate trust and respect and encourage solidarity, and thus help to develop micro-level social capital, which is essential for a culture like Mexico with significant levels of suspicion and class division.