The hypoglycemic effects of Ceriporia lacerata (CL) extracts and mycelium were investigated in vitro and in vivo. The culture broth of CL was extracted with water and 70% ethanol. CL extracts exhibited high inhibitory activities against ${alpha}$-amylase and ${alpha}$-glucosidase. In the oral glucose tolerance test with CL extract and mycelium, glucose level reduction was 25.58 and 24.41%, respectively after 60 min of glucose feeding compared with the glucose groups. Male SD rats were divided into normal control (NC), STZ-induced diabetic group (DM), STZ plus CL extracts treated group (DM-E), and STZ plus mycelium treated group (DM-M). The supplementation of CL extracts and mycelium suppressed plasma glucose and lipid levels compared with the DM group. In addition, the alanine aminotransferase (ALT) and aspartate transaminase (AST) levels of the DM-E group were also decreased with values of 62.08 and 59.83 IU/mL, respectively compared to the DM group. Therefore, it is suggested that the extract and mycelium of CL alleviates the diabetic complications.