Introduction: The aim of this study was to compare the efficacy of vildagliptin as add-on therapy to short-term continuous subcutaneous insulin infusion (CSII) with CSII monotherapy in hospitalized patients with type 2 diabetes mellitus (T2DM). Methods: A total of 200 hospitalized patients with inadequately controlled T2DM were randomized into groups, with one group receiving CSII monotherapy (CSII group, n =100) and the other group receiving CSII plus vildagliptin as add-on (CSII ? Vig group, n = 100). Of these, 191 completed the 7-day trial (CSII group, n = 99; CSII ? Vig group, n = 92) and included in the analysis. The glycemic control and variability of the patients were measured using allday capillary blood glucose (BG) monitoring. Weight and fasting C-peptide levels were evaluated before and after the interventions. Results: Mean BG concentrations during the whole treatment period were lower and the time to reach target BG was reduced in the CSII ? Vig group compared with the CSII group (9.89 ± 3.37 vs. 9.46 ± 3.23 mmol/L, P \ 0.01; 129 ± 4 vs. 94 ± 5 h, P \ 0.01, respectively). Similarly, the indicators of glycemic variability, namely the standard deviation of BG and the largest amplitude of glycemic excursion, were significantly decreased in the CSII ? Vig group compared with the CSII group (2.68 ± 1.05 vs. 2.39 ± 1.00 mmol/L, P \ 0.01; 7.19 ± 2.86 vs. 6.23 ± 2.73 mmol/L, P \ 0.01, respectively). Conclusions: Short-term CSII with vildagliptin as add-on therapy may be an optimized treatment for hospitalized patients with T2DM compared with short-term CSII monotherapy.