The invention relates to iRNA, e.g., double stranded ribonucleic acid (dsRNA), compositions targeting the Serpinc1 gene, and methods of using such iRNA, e.g., dsRNA, compositions to treat a bleeding event in a subject having a hemophilia (e.g., with or without inhibitors).本發明係有關一種靶向Serpinc1基因之iRNA(例如,雙股核糖核酸(dsRNA))組成物、及使用此等iRNA(例如,dsRNA)組成物為患有血友病(例如,帶或不帶抑制劑)之個體治療出血事件之方法。