BACKGROUND Upper-GI vascular ectasias, including angiodysplasia and gastric antral vascular ectasia may present with either acute or chronic bleeding. Endoscopic thermal modalities have been used to control acute bleeding and reduce transfusion requirements. METHODS Endoscopic experience was reviewed for a 6-year period during which 32 patients requiring blood transfusions for upper-GI angiodysplasia or gastric antral vascular ectasia were evaluated. Patients seen during the first 5 years were treated with either Nd:YAG laser photocoagulation or multipolar electrocoagulation. During the most recent 12 months, all patients were treated by argon plasma coagulation. Response to therapy was assessed by change in mean Hb and transfusion requirements. RESULTS Overall, 16 patients were treated by laser photoablation alone; 9, argon plasma coagulation with or without laser; and 7, multipolar electrocoagulation with or without laser. Mean follow-up for all patients was 19 months. After therapy, mean Hb concentration rose from 76 to 114 g/L for patients with gastric antral vascular ectasia and from 85 to 118 g/L for those with angiodysplasia. Endoscopic therapy abolished or reduced transfusion requirements in 93% of patients with gastric antral vascular ectasia and 76% with angiodysplasia. Patients with gastric antral vascular ectasia required a mean of 6 treatment sessions, while those with angiodysplasia required one to two sessions. CONCLUSIONS Endoscopic thermal ablation effectively controls acute bleeding and reduces transfusion requirements in most patients with upper-GI vascular ectasias. Patients with gastric antral vascular ectasia require significantly more treatment sessions to achieve this effect.