The detection of biomarkers, expressed as early onset of carcinogenesis, hold promise for the identification of subjects with a preclinical malignant tumor. However, these biomarkers are present at an ultra-low concentration in bodily fluids. Therefore, ultrasensitive techniques are required for their detection. This work investigated the detection of anti-p53 autoantibodies (anti-p53aAbs) using nanomagnetic beads as antibody capture and anti-IgG functionalized, fluorescence nanoparticles as the detection probe. Specifically, the human p53 protein (p53Ag) immobilized onto nanomagnetic beads, blocked with BSA for capture and separation, and represented as MB-p53Ag/BSA. Anti-IgG antibody conjugated onto FITC-doped silica nanoparticles (FITC@SiO2-NH2-anti-IgGNPs) used as the sensing fluorescent nanobioprobe. A sandwich-type immunoreaction achieved via the Fc-specific FITC@SiO2-NH2-anti-IgG binding to the captured anti-p53aAbs. The signal enhancement achieved by the dissolution of the fluorescent silica nanobioprobes released the encapsulated FITC molecules. The analytical performance evaluated using the FITC@SiO2-NH2-anti-IgGNPs as sensing nanobioprobe and MB-p53Ag/BSA as a nanomagnetic bead for capture is compared to microwell ELISA plate, MTP-p53Ag/BSA. The LoD of the nanomagnetic beads and fluorescent nanobioprobe-based detection was 87.0 fg.mL-1 for the linear range from 1.50 to 500 pg.mL-1 and 27.9 fg.mL-1 for the range of 0.50 to 100 ng.mL-1. For the microwell ELISA placeplate assay, the LoD was 42.0 pg.mL-1 and the linear range was 1.60 to 100 ng.mL-1. The nanomagnetic capture-based assay time was 50 minutes, which is quicker than 3the three hours needed for the microwell ELISA plate assay.