Abstract: Objective To investigate the feasibility and benefits of co-culture of cryopreserved islets with small intestinal submucosa (SIS). Methods Purified rat islets cryopreserved for one month were divided into SIS group and control group, and after culture in standard islet culture media RPMI1640 for 1 week, the morphology and function of the islets were assessed. Results The SIS protects the fragile islets from damage by cryopreservation, and increased the recovery from (60.6±3.3)% to (91.7±1.8)%(P<0.05). Compared with the control group, incubation of the islets of the SIS group in high-glucose (16.7 mmol/L) solution resulted in significantly enhanced insulin secretion (23.7±1.6 vs 12.5±1.1 mU/L, P<0.05). When the islets were incubated in high-glucose solution containing theophylline, the calculated stimulation index of SIS group was about 3-fold higher than that of the control group. Conclusion Co-culture of cryopreserved rat islets with SIS can increase the recovery of islet cells and improve their function.