THe applicaton of radioactive tracers for placental locaization has been introduced as the worthwhile diagnostic method in placenta previa. Recently sup 113mIn are a short half-life with 1.7 hours and no beta particle emission. During the period from May 1970 to August 1971, the placental lesions, clinically. RESULTS : 1. Eight cases out of 19 cases were suggested as placenta previa and the remining 11 cases were turned out to be normal placental location. 2. Among these 8 cases of positive scanning, placenta previa totalis was 6 cases, placenta previa partialis was 1 case and placental previa marginalis was also 1 case. 3. Among 11 cases of normal placental localization, right side placenta was 7 cases and left side, 4 caes. The placental scanning with indium-113m is thought to be one of the simple, safe and rapid method with high accuracy for clinical diagnosis of the placenta previa and placental localization.