Background: Undocumented migrants face many hardships in their everyday life such as poor living conditions, discrimination, and lack of access to healthcare. Previous studies have demonstrated considerable health care needs for psychiatric disorders as well as physical diseases. The aim of this paper was to find out the main barriers that undocumented migrants experience in accessing the Swedish healthcare system and to explore their relation with socioeconomic factors.

Methods: A cross-sectional study with adult undocumented migrants was performed in the three largest cities of Sweden in 2014–2016. Sampling was done via informal networks. A socioeconomic questionnaire was constructed including 22 barriers to health care. Trained field workers conducted the interviews. A principal component analysis was conducted of all barriers to reveal central components. Then, Pearson’s chi-squared test was used to explore the characteristics of undocumented migrants experiencing barriers to care.

Results: Two main components/barriers were extracted: “Fear of being taken by police/authorities”, which was related to fear of disclosure by or in relation to seeking health care, and “Structural and psychosocial factors” which was related to practical obstacles or shame of being ill. Lower age (74.1 % vs 56.0 %), lower level of education (75.0 % vs. 45.1 %), and having no children (70.3 % vs. 48.1 %) were significantly related to a higher likelihood of experiencing a barrier.

Conclusion: Fear of deportation and practical and psychosocial factors constitute hinderance of access to healthcare for undocumented migrants in Sweden. This highlights the importance of clear instructions, both to undocumented migrants and health professionals about the right to health care according to the international law on human rights as well as the law of confidentiality.