The occurrence of marine toxins such as tetrodotoxin (TTX) and saxitoxin (STX) in seafood represents a serious threat to food safety due to their high neurotoxicity, which can result in severe poisoning incidents and, in some cases, fatalities. Most conventional detection techniques are tailored to identify toxins from a single family, making them less effective when both toxins are present simultaneously. Given recent reports of co-occurrence of TTX and STX in seafood, there is a clear demand for advanced bioanalytical multiplexed platforms capable of detecting both toxins in a single assay. This study introduces a novel electrochemical immunosensor designed to detect concurrent TTX and STX. The biosensor features a four-electrode array: two electrodes dedicated to identifying the presence of the toxins in seafood samples, and two control electrodes serving as reference points aligned with established regulatory safety thresholds. By integrating the output signals from the biosensor, the system enables not only toxin identification but also rapid assessment of whether concentrations exceed acceptable safety levels. This multiplexed detection strategy provides a user-friendly, time-efficient tool for screening seafood, contributing to enhanced consumer safety. Moreover, it represents a promising step toward the development of comprehensive biosensing platforms for multi-toxin detection in marine environments.