Clinicians have many unanswered questions during clinical encounters which may impact on the quality and outcomes of decisions made. Provision of online evidence at the point of care is one strategy that provides clinicians with easy access to up-to-date evidence in clinical settings to support evidence-based decision-making. To determine if and when general practitioners use an online evidence system in routine clinical practice, the type of questions for which clinicians seek evidence and the extent to which the system provides clinically useful answers. A prospective cohort study which involved a 4-week clinical trial of Quick Clinical, an online evidence system specifically designed around the needs of general practitioners. Two hundred and twenty-seven clinicians who had a computer with Internet access in their consulting rooms. Computer logs and survey analysis. One hundred and ninety-three general practitioners used the online evidence system to conduct on average 8.7 searches/month. The majority of these (81%) were conducted from consulting rooms and carried out between 9 a.m. and 7 p.m. (83%). The most frequent searches conducted related to diagnosis (40%) and treatment (35%). 83% of clinicians believed that Quick Clinical (QC) had the potential to improve patient care, and one in four users reported direct experience of improvements in care. In 73% of queries with clinician feedback participants reported that they were able to find clinically useful information during their routine work. General practitioners will use an online evidence retrieval system in routine practice, and report that its use improves the quality of patient care.