Introduction: According to the report of World Cancer Research Fund International in 2012. Prostate cancer (PC) and bladder cancer (BC) are the 4th and 9th common cancer worldwide. Hematuria is the common symptom of patients with PC or BC. Traditional ways for diagnosis of each kind of cancer are either low sensitive or invasive, i.e. prostate specific antigen (PSA) testing for PC and cystoscope for BC. Therefore, a reliable and noninvasive method for early diagnosis is required. Engrailed-2 (EN2) is a biomarker of PC with sensitivity of 66.7% and specificity of 86.3%, which is more sensitive than the traditional marker. Apolipoprotein A1 (APOA1) is a biomarker of BC with sensitivity of 94.6% and specificity of 92.0%. In this study, a magnetic graphene-based biosensor was developed to detect EN2 and APOA1 simultaneously for early diagnosis of PC and BC