Impedance spectroscopy of biomolecules is a growing domain that deals with the study and analysis of various analyte molecules to express high-utility applications. The analytes can be directly extracted from the environment or are derived from nature through some biological/biochemical processes. The common biological analytes are drugs, DNA/RNA, cells, pathogenic bacteria, enzymes, ions, and gases. Impedance analysis measures the impedance characteristics of an analyte over a long-range frequency sweep and interprets its behavior for various frequency domains. This detection method can be utilized for analysis in an independent or integrated format with various discrete analysis/supporting techniques. Along with extensive application in the biomedical field, this technique is also used in several other applications like the analysis of electroactive polymer thin films, colloids, lubricants, paints, and batteries/fuel cells. This chapter explains the utility of impedance analysis through a detailed explanation of fundamental principles, its several components, equivalent circuit diagrams, and their common applications.