We assessed primary care providers' perception of a health information exchange system (HIE) based on IHE XDS. The HIE will be part of a regional health network in the metropolitan area of Braunschweig, Lower Saxony, Germany. An application enabling access to medical documents in an XDS Affinity Domain was developed. We examined usability and factors related to user acceptance. User perception was probed using system usability scale (SUS) and semi-structured interviews. The evaluation was performed on 7 participants. The SUS showed an above average usability with a median score of 77.5. During interviews, participants submitted suggestions for additional features and improvement of usability. Poor integration of functionality into existing workflows was most frequently criticized. While usability was well perceived by primary care providers, challenges remain in adoption of XDS based IHE. To speed up document access in time-critical domains, we suggest use of complementary methods, enabling directed communication flows.