The efficacy of several pulpotomy methods were evaluated histologically on animal model using 6 beagles. At 1, 4, 6 weeks after pulpotomy, animals were sacrificed by perfusion method, Histomorphometric analysis was performed using computerized image analyzing system. Statistical comparisons were done using SPSS program. The following results were obtained: 1. Tissue responses after ferric sulfate treatment mainly consisted of fibrous surface layer with the underneath pulpal tissue layer containing well-preserved odontoblasts. 2. Bleeding, fibrosis and necrosis are the main reactions obsereved in electrosurgical pulpotomy and the normal pulpal tissues were limited to the apical portion. 3. In the aspect of preserving the normal pulpal tissue, ferric sulfate pulpotomy was evaluated to be superior to formocresol or electrosurgical pulpotomy.