In the present work, we have developed an electrochemical aptasensor for detection of breast cancer biomarker protein, mucin1 (MUC1). Gold nanoparticles (AuNPs) and graphene oxide (GO) doped Poly(3,4-ethylenedioxythiophene) (PEDOT) nanocomposite films were deposited onto the surface of fluorine tin oxide (FPO) glass sheets by electropolymerization using chronoamperometry technique at a potential of 1.0 V for 180 s. MUC1 specific biotinylated aptamer was immobilized onto the AuNPs-GO-PEDOT nanocomposite film via biotin-avidin interaction strategy. The biotinylated aptamer immobilized electrodes were characterized using contact angle measurement studies, FT-IR and electrochemical techniques. Optimization parameters like aptamer concentration and response time were also studied. The developed aptaelectrode was used for the sensing of MUC1 with limit of detection (LOD) of about 1 fg/mL (0.031 fM). The stability and reusability of the aptaelectrode was observed to be 14 days and 8 times, respectively. The fabricated aptaelectrode was also applied for the determination of MUC1 in spiked human serum samples with 85-93% recovery.