Aplasia or hypoplasia of great saphenous vein (GSV) is relatively common. Most of them are segmental and localized around the knee. They rarely extend to the inguinal area, yet in case of this, the anterior accessory saphenous vein (AASV) is the most common connecting vein. We report a case of a 22-year-old male who underwent surgery for pain and heaviness of the right calf. He had the hypoplasia of right GSV extended from below the popliteal crease to near the saphenofemoral junction with posterior ASV (PASV) as a connecting vein. Significant reflux was observed in PASV and GSV which are proximal to PASV. High ligation and stripping was performed, and symptoms improved after surgery. In this report, the author discussed a rare case of long-segment hypoplasia of GSV with PASV as a connecting vein.