Telaprevir and Boceprevir are the first direct acting antivirals approved for chronic hepatitis C in combination with peg-interferon alfa and ribavirin.Pancytopenia due to myelotoxicity caused by these drugs may occur,but severe hematological abnormalities or aplastic anemia(AA) have not been described.We collected all cases of severe pancytopenia observed during triple therapy with telaprevir in four Spanish centers since approval of the drug in 2011.Among 142 cirrhotic patients receiving treatment,7 cases of severe pancytopenia(5%) were identified and three were consistent with the diagnosis of AA.Mean age was 59 years,five patients had compensated cirrhosis and two patients had severe hepatitis C recurrence after liver transplantation.Severe pancytopenia was diagnosed a median of 10 wk after the initiation of therapy.Three patients had pre-treatment hematological abnormalities related to splenomegaly.In six patients,antiviral treatment was interrupted at the onset of hematological abnormalities.Two patients died due to septic complications and one patient due to acute alveolar hemorrhage.The remaining patients recovered.Severe pancytopenia and especially AA,are not rare during triple therapy with telaprevir in patients with advanced liver disease.Close monitoring is imperative in this setting to promptly detect serious hematological disorders and to prevent further complications. Telaprevir and Boceprevir are the first direct acting antivirals approved for chronic hepatitis C in combination with peg-interferon alfa and ribavirin. Pancy topenia due to myelotoxicity caused by these drugs may occur, but severe hematological abnormalities or aplastic anemia (AA) have not been described. We collected all cases of severe pancytopenia observed during triple therapy with telaprevir in four Spanish centers since approval of the drug in 2011. Among 142 cirrhotic patients receiving treatment, 7 cases of severe pancytopenia (5%) were identified and three were consistent with the diagnosis of AA .Mean age was 59 years, five patients had compensated cirrhosis and two patients had severe hepatitis C recurrence after liver transplantation .Severe pancytopenia was diagnosed a median of 10 wk after the initiation of therapy.Three patients had pre-treatment hematological abnormalities related to splenomegaly.In six patients, antiviral treatment was interrupted at the onset of hematological a bnormalities.Two patients died due to septic complications and one patient due to acute alveolar hemorrhage.The remaining patients recovered. Severe pancytopenia and especially AA, are not rare during triple therapy with telaprevir in patients with advanced liver disease .Close monitoring is imperative in this setting to promptly detect serious hematological disorders and to prevent further complications.