In the present work, self-assembled 3D flower-like beta-Ni(OH)(2)@CDs hybrid nanostructures were synthesized by a simple and low-cost procedure using the CTAB-assisted hydrothermal method. Characterization of synthesized nanocomposite was performed by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), FT-IR and electrochemical techniques. Then, this product was used to fabricate a new nitrite sensor by drop casting 5 ml of its suspension (5 mg/mL prepared in Milli-Q water) on a cleaned glassy carbon electrode surface. The effects of some parameters on the sensor response toward the electro-oxidation of nitrite such as pH, and scan rate were evaluated and optimized to achieve higher sensitivity. The novel amperometric sensor exhibited excellent electrocatalytic activity toward the electro-oxidation of nitrite in the linear range of concentration 2.5 x 10(-6)M to 1.2 x 10(-3)M with a low detection limit of 0.03 mM(S/N = 3) and very good detection sensitivity of 647.8 mAmM(-1) cm(-2). The favorable advantages such as good repeatability and reproducibility, high sensitivity, long-term stability and anti-interference make this sensor very attractive for on-site environmental monitoring of nitrite in water samples with satisfied recovery. (C) 2018 Elsevier Ltd. All rights reserved.