Spain has grown economically due to the recent boosts in the industrial sector, the agricultural sector, construction and services. Those who carry out agricultural tasks are mainly undocumented immigrants living in marginal neighborhoods. Objectives: to know the perception of undocumented Moroccan migrants living in marginal neighborhoods regarding access to the Public Health System. Methods: A qualitative method with a phenomenological approach was used to get closer to the experience of the participants in the study. In this work, 24 semi-structured interviews were conducted following a guide with a set of open questions to facilitate an in-depth discussion of the topics of interest. The participants were given an informed consent form, which guaranteed anonymity and confidentiality regarding the information obtained. For this, codes were used to identify them. The data were stored, managed, classified, and organized with the ATLAS-ti 9 software. Results: access and use of health services by the immigrants in the study was difficult due to communication problems related to language and culture, the discriminatory attitude and lack of cultural competence of health personnel, and the location of the neighborhoods (which were marginal far from urban centers), as well as the lack of transportation to health centers. Conclusions: it is an ethical imperative of the Health System to offer greater attention to the population in situations of extreme vulnerability, implement intercultural mediators and train health professionals in cultural competence.