Abstract Background Case management is a term used to describe the activities performed by a physician or other health care professional to ensure the coordination of medical services required by a patient. Managed care requires the incorporation of information pertaining to patient evaluation, treatment planning, referrals, and follow-up care to ensure that payment for services is received and that care is ongoing and comprehensive. The objective of this review was to assess the efficacy of case management in patients with type 2 diabetes mellitus with respect to outcomes such as glycosylated hemoglobin (HbA 1c ), systolic blood pressure (SBP), diastolic blood pressure (DBP), and low-density lipoprotein (LDL). Methods Databases including PubMed, Embase, Web of Science, the Cochrane Library, the China National Knowledge Infrastructure (CNKI), VIP, Wan Fang and the Chinese Biomedical Literature Database (CBM) were searched for randomized controlled trials (RCTs) dating as late as Jan, 2015. Reference sections of the included studies were also searched. Results Twelve studies, involving 11 RCTs that evaluated a total of 4000 patients, were included in this analysis. Two of the 12 studies evaluated the same RCT. Seven of the 12 studies reported HbA 1c as an outcome, and three trials reported changes in SBP, DBP and LDL levels as outcomes. The pooled results indicated that statistically significant improvements in HbA 1c (MD = −0.35, 95% CI (−0.68, −0.02), P = 0.04) and LDL levels (MD = −2.49, 95% CI (−4.04, −0.93), P = 0.002) were associated with the case management group compared with control group; however, no statistically significant differences in DBP (MD = −0.08, 95% CI (−0.68, 0.52), P = 0.8) and SBP (MD = −0.96, 95% CI (−5.77, 3.84), P = 0.69) were observed. Conclusions Case management was effective in improving HbA 1c and LDL levels in patients with type 2 diabetes mellitus. Although no statistically significant differences in DBP and SBP between the case management group and the control group were observed, further research is required to draw a conclusion about the effect of managed care on these outcomes. Based on this meta-analysis of clinical trials, we conclude that case management offers an effective clinical method for the treatment of type 2 diabetes.