Background: Access to health care is a global public problem. In French Guiana, there exists social inequalities which are specially marked amongst immigrants who make up a third of the population. Health care inequalities are prevalent. The objective of this study was to determine factors associated with why health care amongst the poor population of Cayenne was renounced. Study design The study was cross sectional. It focused on knowledge, attitudes, practices and beliefs of the population living in poor neighborhoods of the Cayenne area. Methods: Populations coming at the Red Cross mobile screening unit in poor urban areas of Cayenne were surveyed from July 2013 to June 2014. Structured questionnaires consisted of 93 questions. Written informed consent was requested at the beginning of the questionnaire. The predictors for renouncing medical care were determined using logistic regression models and tree analysis. Results: Twenty percent of persons had renounced care. Logistic regression showed that renouncement of health care was negatively associated with having no regular physician Adjusted Odds Ratio (AOR)=0.43 (95%CI=0.24-0.79) and positively associated with being embarrassed to ask certain questions AOR=6.81 (95%CI=3.98-11.65) and having been previously refused health care by a doctor AOR=3.08 (95%CI=1.43-6.65) . Tree analysis also showed that three of these variables were linked to renouncement, with feeling shy to ask certain questions as the first branching. Conclusion: Although most people felt it was easy to see a doctor, one in five had renounced health care. The variables identified by the models suggest vulnerable persons generally had previous negative encounters with the health system and felt unwanted or non eligible for healthcare. Health care mediation and welcoming staff may be simple solutions to the above problems which were underscored in our observations.