Biomarkers are molecular or cellular diagnostic tools, measured in biological samples such as blood, saliva and urine. It is used as an indicator to measure and evaluate biological processes, pharmacological response and pathogenic processes. Some of the major types of biomarkers are prognostic, predictive, pharmacodynamic and efficacy response biomarker. A variety of biomarkers are available for biological systems such as immune system, cardiovascular system and metabolic system. Biomarkers are used to detect, predict disease susceptibility and monitor disease progression for infectious diseases, cancer, metabolic diseases, central nervous system disease and autoimmune diseases. Biomarker technologies have its applications in diagnosis and prognostic treatment for exposure of harmful chemicals, drug formulation and development and increasing implementation in disease diagnosis. Many drugs fail in clinical trials due to metabolism, toxicity, absorption, etc. Biomarkers are special tools usually used in clinical studies to determine the effects and desired results of drug in early stages of development. Biomarkers are cost effective and reliable for developing, monitoring and predicting efficiency of drugs.