This research explores the satisfaction gap between the expectations of medical doctors when using the Internet to search for health-related information, and the confirmations they receive following the use of specific information sources to meet their information needs. We executed a quantitative study on 303 medical doctors to capture their online information-seeking behavior. Results suggest that authoritative online information sources are strongly related with the derived satisfaction of medical doctors' online information needs, whilst expectation fulfillment is not related with usage of non-authoritative sources. Nevertheless, doctors' perceptions regarding the information quality of online sources, and discerning personal constraints regarding Internet use, moderate the relationship between online source usage and the effectuation of their expectations.