We report on the design and fabrication of a hybrid sensor that integrates transmission-mode localized surface plasmonic resonance (LSPR) into a quartz crystal microbalance (QCM) for studying biochemical surface reactions. The coupling of LSPR nanostructures and a QCM allows optical spectra and QCM resonant frequency shifts to be recorded simultaneously and analyzed in real time for a given surface adsorption process. This integration simplifies the conventional combination of SPR and QCM and has the potential to be miniaturized for application in point-of-care (POC) diagnostics. The influence of antibody-antigen recognition effect on both the QCM and LSPR has been analyzed and discussed. •We hybridised a LSPR and QCM sensor that simultaneously records the optical and acoustic signal in real time for a given surface adsorption process to eliminate the variations of the experimental conditions.•We detailed the design and simulation of the hybridised LSPR and QCM device and experimentally assess its performance. The experimental data match well with the simulations, further proving the design concept.•We used the hybridised chip in a biologically relevant immunoassay showing its potential for practical biosensing.•Our technology provides a miniaturized dual sensor platform for simultaneous measurement that is compatible with incorporation into future point-of-care and portable devices.