Hydroxylamine (HA), a derivative of ammonium belongs to an important class of reducing agents, which are commonly used for synthesis of pharmaceutical intermediates and final drug substances. However, it is a well-known mutagen, which induces highly specific mutations withthe nucleic acid cytosine. Modest levels of hydroxylamine can be toxic and harmful to human, animals, and even plants [1]. As an electroactive compound, the hydroxylamine has alsoattracted much interest of electrochemists. But, it is impossible to measure the concentrations of this compound using bare electrodes [2]. One promising method is the use of chemically modified electrodes (CMEs) containing particularly selected redox active materials (homogenouscatalysts) immobilized on conventional electrode materials. Among conventional electrodes carbon paste electrode (CPE) is one of the most conductive matrixes for preparing CME. Recently, a wide variety of compounds have been used as the electron transfer mediators for the modification of electrode surfaces with various approaches [3]. In this work a ferrocenederivative compound, 2,7-bis (ferrocenyl ethynyl) fluoren-9-one (2,7-BFE), was synthesized and used to construct a modified graphene paste electrode. The electrooxidation of hydroxylamine atthe surface of the modified electrode was studied using cyclic voltammetry (CV), chronoamperometry (CHA), and square wave voltammetry (SWV). Under the optimizedconditions, the square wave voltammetric peak current of hydroxylamine increased linearly with hydroxylamine concentration in the range of 2.0×10-7 to 2.5×10-4 M and detection limit of 9.0×10-8 M was obtained for hydroxylamine. The Tafel slope of 117.0 mV obtained in this case agrees well with the involvement of one electron in the rate determining step of the electrode process, assuming a charge transfer coefficient of α=0.49. Finally, this modified electrode was used for determination of hydroxylamine in some water samples.