Adiponectin is an adipocyte-specific secretory hormone that can increase insulin sensitivity and promote adipocyte differentiation. Administration of adiponectin to obese or diabetic mice reduces plasma glucose and free fatty acid levels. Green tea polyphenols posses many pharmacological activities such as antioxidant, anti-inflammatory, anti-obesity, and anti-diabetic activities. To investigate whether green tea polyphenols have an effect on the regulation of adiponectin, we measured expression and secretion levels of adiponectin protein after treatment of each green tea polyphenols in 3T3L1 adipocytes. We found that (-)-catechin enhanced the expression and secretion of adiponectin protein in a dose- and time-dependent manner. Furthermore, treatment of (-)-catechin increased insulin-dependent glucose uptake in differentiated adipocytes, and augmented the expression of adipogenic marker genes, including PPAR, CEBP, FAS, and SCD-1, when (-)-catechin was treated during adipocyte differentiation. In search of the molecular mechanism responsible for inducible effect of (-)-catechin on the adiponectin expression, we found that (-)-catechin markedly suppresses the expression of Kruppel-like factor 7 (KLF7) protein, which has recently been reported to inhibit the expression of adiponectin and other adipogenesis related genes, including leptin, PPAR, C/EBP and aP2 in adipocytes. KLF7 is a transcription factor in adipocyte and plays an important role in the pathogenesis of Type 2 diabetes. Taken together, these data suggest that the up-regulation of adiponectin protein by (-)-catechin may involve, at least in part, suppression of KLF7 in 3T3-L1 cells.