Objectives : Gamisoyo-san complex prescription were made with Angelicae Gigantis Radix, Paeoniae Radix, Atractylodes rhizome white, Hoelen, Bupleuri Radix, Moutan Cortex Radicis, Gardeniae Fructus, Zingiberis Rhizoma Crudus, Menthae Herba. The purpose of this study was to research the whitening effect of the extract from Gamisoyo-san, which is one of the used herbal complex prescription. Methods : This study investigated inhibitory effect of Gamisoyo-san in tyrosinase activity. Cell viability were performed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Then, Gamisoyo-san measured reversed-transcription-PCR for mRNA expression using B16F10 mouse melanoma cells. Results : For whitening effects, the tyrosinase inhibition effect of extract was shown to 52.4% at $5,000{mu}g/m{ell}$ concentration. The cell viability on B16F10 melanoma cells of Gamisoyo-san extract showed higher than 75% at $1,000{mu}g/m{ell}$ concentration. In this study, an experiment was performed by setting the non-toxic concentration range of 50, 150, $250{mu}g/m{ell}$. The Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as a positive control. The microphthalmia-associated transcription factor (MITF), tyrosinase related protein-1 (TRP-1), tyrosinase related protein-2 (TRP-2), tyrosinase mRNA expression inhibitory by reverse transcription-PCR of Gamisoyo-san extract were decreased by 95.3%, 98.8%, 96.3% and 49.5% at $250{mu}g/m{ell}$ which the highest concentration. Conclusions : All these findings could verify that whitening effects of Gamisoyo-san extract by tyrosinase inhibitory activity and mRNA expression. The Gamisoyo-san could be used as material for functional cosmetics, such as skin whitening products.