The Marienambulanz in Graz, which was founded in 1999, is an outpatient clinic aiming to provide free medical services for marginalized groups. Medical and socioeconomic data of patients at the outpatient clinic have been collected electronically since 2003. The purpose of this study was to find out which persons were treated at the Marienambulanz in the last seven years (2003-2009) and to find out the most frequent reasons for attending the Marienambulanz. We analysed existing medical data descriptively in order to find out the four most frequent reasons for going to the outpatient clinic, the nationality of the patients and whether or not the patients had insurance coverage. Since 2003, 3,652 patients (2,342 men and 1,310 women) have been treated at the Marienambulanz. The majority of patients came either for an initial medical examination, for medication or for further thorough examinations including advice about general health and - if necessary - for childcare. Interestingly, more than 60% of the patients were insured. The Marienambulanz provides medical assistance for uninsured persons and for marginalized insured persons who do not make use of the regular health care system. It can be argued that the regular Austrian health care system fails to provide health care for marginalized groups. The Marienambulanz in Graz, as a low-threshold institution, serves the purpose of bridging the gap to the regular health care system for marginalized groups.