This thesis is an exploratory study of perceptions of health and illness, etiological agents and factors influencing medical choice of individuals living in two barrios, La Juanita and San La?zaro, within the Cuban City of Cienfuegos. Research focuses on the three main arenas of health care: customary, traditional and conventional medicine. Using work from Laguerre, emphasis is placed on the media through which medical knowledge is reproduced within the study population. Next I examine the social interaction between these systems with the help of Arthur Kleinman's model on medical pluralism. Data obtained from a survey, semi-structured interviews and participant observation indicate that while individuals defined health and illness in terms of physical ailments, etiological agents varied between the strictly natural, to supernatural (e.g. the evil eye, witchcraft, envious individuals, etc.). Social factors and the characteristics of heath services and illnesses were among the major influences on medical behavior and decision-making. All individuals reported a combined use of the aforementioned medical systems and expressed faith in the effectiveness of conventional medicine. All exhibited basic knowledge of customary medicine, however belief in traditional forms of medicine varied. The household was listed as the main focal point through which medical knowledge is reproduced. Next in importance was the media, family doctors and religious orientations. Finally, interviews with doctors, 'curanderos' and informants from both barrios indicate a complementary health care system with 'casas particulares' (private homes) and pharmacies providing increased access to all 'materia medica'.