Transdermal drug delivery system has been studies for several decades as an alternative tool. Even though it has many advantages such as stability of drug to the destination, safety to liver, there are many limitations to across stratum corneum. Microneedle can perforate the skin directly which make it possible for drug to penetrate. 4 sizes of DTS(Diskmicroneedle Therapy System), 0.25mm, 0.5mm, 1.0mm, 1.5mm, was used to perforate skin and tracking rhodamine B base showed the effect of penetration of drug by microneedle. To detect the status of rhodamin B base visually, after 6h of delivery skin was frozen sectioned and investigated by fluorescence microscopy and to detect the penetrated amounts through skin after 24h, 48h, aliquot from receptor compartment of Franz diffusion cell was readed at 543nm by microplate reader. DTS made pores for rhodamine B base to penetrate through the skin effectively and this effect was proportional to size of microneedle. Live skin could make the molecules applied to spread widely by blood circulation otherwise dead skin accumulated the drug as times went by. Result will be discussed Diskmicroneedle is the effective transdermal delivery system and the size has to be chosen considerably. This study was supported by a grant of the Korea Healthcare technology R&D Project, Ministry for Health, Welfare and Family Affairs, Republic of Korea. (A090180)