OBJECTIVES:Juglans (J.) regia L. is known to possess many biological properties. In this study, antihemolytic activity of methanol extract of Juglans regia L. flower were investigated. MATERIALS AND METHODS:Antihemolytic activities of Juglans regia L. flowers were evaluated by various in vitro assays. In addition, scavenging of hydrogen peroxide and mineral contents of flowers were determined using atomic absorption spectroscopy. RESULTS:Extract showed good antihemolytic activity against H2O2 and CuOOH induced hemolysis in comparison with control. Extract was capable of scavenging H2O2 in a concentration dependent manner. IC50 for H2O2 scavenging activity was 311±12.8 µg ml-1. The amount of eight elements was determined and was in the order: Mn > Cu > Fe > Zn. CONCLUSIONS:Our study indicate that J. regia flower has remarkable antihemolytic activity, which maybe result of its high phenol and flavonoid contents, especially quercetin.