Several investigators have reported clinical experience of medial plantar septo-cutaneous flap for reconstruction for soft tissue defect of the hand and digits. Jayme and Hamilton first described the anatomy of superficial branch of medial division of the medial plantar artery used in this flap through cadavaric study in 1997. But, they had a few cases for this flap and there was no anatomic study in Korean. We experienced the reliability of medial plantar septo-cutaneous flap for reconstruction for soft tissue defect of hand and digits through an anatomic study (20 fresh specimens dissected) and clinical application (17 patients). An anatomic study revealed that there were differences in diameter and length of the vessels between Korean and Caucasian. The diameter of vessels in Korean is larger than Caucasian one in each area. Based on this anatomic knowledge, we could harvest this flap safely, and have performed reconstruction on 17 patients with soft tissue defects of hand and digits using a thin, flexible medial plantar septo-cutaneous flap similar to the volar aspect of the hand and digits in anatomical characteristics of the skin and subcutaneous tissue covering. The vessels used for this flap were superficial branches of medial division of the medial plantar artery and vena comitants, or the subcutaneous veins. The mean size of the flap was $2.82cm{ imes}4.15cm$. All the flaps survived without significant complications. A medial plantar septo-cutaneous flap possesses several advantages : (1) It is very thin in comparison with other standard free flap; (2) it has two draining venous pathways; (3) it provides a good color and texture match for hand and finger; (4) a good recovery of protective sensation is achievable.