A rapid magnetoimmunosensor for the simultaneous determination of two cardiac biomarkers, amino-terminal pro-B-type natriuretic peptide (NT-proBNP) and C-reactive protein (CRP), in human serum is described. Specific capture antibodies were covalently immobilized onto carboxylic acid-modified magnetic beads. The quantification of NT-proBNP and CRP was performed by using indirect competitive and sandwich configurations, respectively, and horseradish peroxidase-labeled tracers. The use of dual screen-printed carbon electrodes allowed the achievement of simultaneous independent amperometric readout for each cardiac biomarker. The developed methodology showed very low limits of detection (0.47 ng mL−1). An international standard for CRP serum spiked with NT-proBNP was analyzed to evaluate the usefulness of the magnetoimmunosensor.