The adoption of health information systems is seen world wide as one method to mitigate the widening health care demand and supply gap. The purpose of this review was to identify the current state of knowledge about health information systems adoption in primary care. The goal was to understand factors and influencers affecting implementation outcomes from previous health information systems implementations experiences. A comprehensive systematic literature review of peer reviewed and grey literature was undertaken to identify the current state of knowledge regarding the implementation of health information systems. A total of 6 databases, 27 journal websites, 20 websites from grey sources, 9 websites from medical colleges and professional associations as well as 22 government/commission websites were searched. The searches returned almost 3700 article titles. Eighty-six articles met our inclusion and exclusion criteria. Articles show that systems' graphical user interface design quality, feature functionality, project management, procurement and users' previous experience affect implementation outcomes. Implementers had concerns about factors such as privacy, patient safety, provider/patient relations, staff anxiety, time factors, quality of care, finances, efficiency, and liability. The review showed that implementers can insulate the project from such concerns by establishing strong leadership, using project management techniques, establishing standards and training their staff to ensure such risks do not compromise implementation success. The review revealed the concept of socio-technical factors, or "fit" factors, that complicate health information systems deployment. The socio-technical perspective considers how the technical features of a health information system interact with the social features of a health care work environment. The review showed that quality of care, patient safety and provider/patient relations were not, positively or negatively, affected by systems implementation. The fact that no articles were found reviewing the benefits or drawbacks of health information systems accruing to patients should be concern to adopters, payers and jurisdictions. No studies were found that compared how provider-patient interactions in interviews are effected when providers used electronic health information systems as opposed to the paper equivalent. Very little information was available about privacy and liability.