The increasing incidences and routine monitoring of endocrine disrupting chemicals (EDCs) in water samples, necessitates the development of selective yet sensitive biosensor for 17β-Estradiol (E2). Herein, we report a capacitive immunosensor for rapid and sensitive detection of E2. The immunosensor was constructed by functionalizing the electrode using self-assembled mono-layers and coupled with specific monoclonal antibody (mAb) against E2. The surface morphology of developed immunosensor was characterized using Fourier Transform Infra Red spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and fluorescence imaging. The antigen-antibody (mAb-E2) interaction was quantified by measuring the capacitance change in the frequency range 1–100KHz, at ac potential of 10mV. Under optimized experimental conditions, the change in capacitance was found to be linear in the concentration range 5–200pgmL−1 for E2 in the buffer and water samples. The limit of detection (LOD) was found to be 1pgml−1 (S/N=3) with the sensitivity of 1.4% capacitance change per decade. For practical application, the performance of immunosensor was demonstrated in packaged water sample. The obtained recoveries were 97.96 to 102% with a maximum relative standard deviation (%RSD=1.43, n=3) with a short analysis time of 10min. The analytical figures of merit for developed label free immunosensor meets regulatory requirements of EU (50pgmL−1), Codex (5pgmL−1) and USFDA (120pgmL−1) standards. Cross reactivity against Stigmasterol and BPA was found to be 18% and 8% respectively. The E2 sensor was operationally found stable till 14days with 70% of initial response.