Wearable devices have become a standard health care intervention with emerging health care technologies. These devices are designed to promote healthy behaviors and decrease risk for chronic disease like cardiovascular disease and diabetes. The purpose of this study was to provide evidence of the benefit of wearable devices in chronic disease outcomes among adults. Systematic search of PubMed, Web of Science, World Health Organization international clinical trials registry platform, BMC ISRCTN registry, and the Institute of Electrical and Electronics Engineers was performed based upon the PRISMA guideline. Included articles were randomized controlled trials or quasi-experimental studies with health outcomes published in English up to October 2018. Studies focusing on adults were selected. Three investigators reviewed the selected publications and made agreement on final selection. Of a total of 550 publications extracted, 6 studies met the final criteria. There was little indication that wearable devices provide a benefit for health outcomes. Of the 6 studies examined, only one study showed a significant reduction for weight loss among participants who used wearable devices. No significant reduction was discovered in cholesterol or blood pressure. Among the 6 studies, only one study examined hemoglobin A1c, and it showed a significant reduction in older patients with type 2 diabetes. The current literature evaluating wearable devices indicates little benefit of the devices on chronic disease health outcomes. Wearable devices play a role as a facilitator in motivating and accelerating physical activity, but current data do not suggest other consistent health benefits.