Detection of biomarkers plays a pivotal role in the early identification and control of various diseases, including cardiovascular diseases (CVDs), cancer, diabetes, and bacterial and viral infections. Electrochemical impedance spectroscopy (EIS) has emerged as a promising tool for the detection of biomarkers, offering high sensitivity, quick response, and a cost-effective approach. This chapter provides an in-depth exploration of impedimetric sensors for various diseases. The chapter begins with an overview of the fundamental principles of EIS and circuit fitting techniques, followed by a detailed discussion on biomarkers for various diseases like cancer, diabetes, bacterial and viral, and cardiovascular diseases. In particular, the chapter highlights the importance of detecting biomarkers including C-reactive protein (CRP), cardiac troponin I (cTnI), BRCA1, BRCA2, MUC 1, fibrinogen, lipoprotein, homocysteine, and glycated albumin (GA) in cardiovascular diseases, cancer and diabetes, showcasing how impedimetric sensors offer sensitive, specific and cost-effective solutions for detection. Overall, this chapter underscores the need for biomarker detection, describes the types of available impedimetric sensors, discusses the advantages of impedimetric techniques, and paves the way for future advancements in sensor technology for biomarker detection.