Troglitazone is insulin-sensitizing agents which improve hyperglycemia and hyperinsulinemia by increasing insulin responsiveness and/or sensitivity in obese and type 2 diabetic. To investigate whether this compound could increase the adipogenic gene marker, GLUT4, we add troglitazone on common 3T3-L1 adipogenic induction media. The expression was observed by semi quantitative real time PCR using beta actin as reference gene. Furthermore, the 3T3-L1 differentiated cells was stained by oil red O staining to observe the morphological changing during differentiation. In fully differentiated adipocytes, the GLUT4 over expressed in 3T3-L1 treated by troglitazone. These expression was higher than 3T3-L1 cells treated only adipogenic induction media, and without adipogenic media at all. Moreover, the successfully 3T3-L1 differentiated cells also changed, and seen as rounded adipocyte cells with red droplet lipids around the nuclear.