BACKGROUND Diabetes mellitus (DM) is a critical medical problem that can make people more likely to develop infectious complications, even sepsis. However, the influence of DM on the outcomes of septic patients is still controversial. Thus, we conducted the present meta-analysis to investigate whether DM worsens outcomes of septic patients. MATERIAL AND METHODS We searched studies from PubMed, Embase, and Cochrane Library databases from 1966 to July 1, 2016. The primary outcome we chose was 28-day or 30-day mortality or in-hospital mortality. RESULTS Our meta-analysis of 10 enrolled studies performed between 2000 and 2016 shows that the mortality rate of septic patients with DM was slightly lower than that of non-diabetic patients (risk ratio [RR]=0.97, 95% confidence interval [CI]: 0.96 to 0.98, P<0.00001). On the other hand, septic patients with DM had a shorter hospital stay (weighted mean difference (WMD)=-2.27, 95% CI: -4.11 to -0.44, P=0.01), a higher incidence rate of AKI (RR=1.56, 95% CI: 1.25 to 1.95, P<0.001), and a similar incidence of respiratory dysfunction (RR=0.86, 95% CI: 0.71 to 1.04, P=0.11) compared with those without DM. CONCLUSIONS The results from the meta-analysis suggest that DM does not impair the outcome of patients with sepsis, and the incidence of acute kidney injury increases dramatically in septic patients with DM. Due to the limitations of the analysis, more well-designed trials are still necessary.