Display omitted •Facile and environment-friendly synthesis of MoS2@rGO nanohybrid.•Electrophoretic deposition of MoS2@rGO nanohybrid onto ITO substrate enhances electrochemical performance.•The device is label free, ultra-sensitivity with good selective and stability.•Great potential for cancer biomarker detection in spiked samples.•Can be an alternate platform for early determination of cancer biomarkers. An ultrasensitive, electrochemical biosensor has been fabricated by utilizing molybdenum disulfide (MoS2) grafted reduced graphene oxide (MoS2@rGO) nanohybrid as a sensing platform. Biomolecular-assisted synthetic method was adopted to synthesize MoS2@rGO nanohybrid, where L-cys was used to reduce GO. The MoS2@rGO nanohybrid exhibits improved electrochemical performance when it has been electrophoretically deposited onto the indium tin oxide (ITO) coated glass substrate. Further, epithelialcell adhesion moleculeantibodies (anti-EpCAM) specific to cancer biomarker has been covalently immobilized on the MoS2@rGO/ITO electrodes for label-free detection of EpCAM. Electrochemical results confirm that anti-EpCAM/MoS2@rGO/ITO based biosensor can detect EpCAM in the concentration range of 0.001–20 ng mL−1 with a detection limit of 44.22 fg mL−1 (S/N = 3). The biosensor's excellent analytical performance has been attributed to the efficient immobilization of EpCAM antibodies on the MoS2@rGO surface, which results in high specificity for EpCAM antigen. The fabricated biosensor showed good selectivity, reproducibility, and stability. The successful detection of EpCAM antigen in spiked samples (human saliva, serum and urine) makes this platform an alternative method for early screening of cancer biomarker.