Purpose: To evaluate how well general practitioners (GPs) manage and respond to laboratory results for patients with diabetes mellitus (DM) and cardiovascular disease (CVD). Data sources: MEDLINE, CINAHL, Embase, EBM reviews, ProQuest and Scopus. Study selection: Peer-reviewed journal articles published between 2000 and 2015 that assessed GPs' management of laboratory results for patients with DM or CVD. Data extraction: Study design and demographics, laboratory tests and key findings relating to GP management of laboratory results were extracted from studies. Results of data synthesis: Thirteen articles were included, comprising seven studies which utilized surveys, four observational studies, one cohort study and one randomized controlled trial. Findings indicate that GPs often overestimate the risk of complications associated with DM and CVD based on laboratory results and have unrealistically high expectations regarding the precision of laboratory tests. Considerable variation existed in the use of repeat testing for diagnostic confirmation and in GPs' identification of the difference between two consecutive results required to indicate a change in patient condition. GPs also often failed to initiate appropriate treatment for patients with DM and CVD based on laboratory results. Feedback to GPs about their test ordering patterns and educational messages on laboratory results improved clinical outcomes. Conclusion: Evidence about how well GPs manage results and its impact on patient outcomes remains weak and inconclusive. This review identified a number of areas where interventions could support GPs to improve the interpretation and management of laboratory test results, including feedback to GPs and educational messages on test result reports.