Bioanalytical methods are used to analyse an analyte in a biological matrix. Bioanalytical method validation is the process of determining the suitability of the given bioanalytical methodology for providing the required analytical data. Validation of the bioanalytical methods demonstrate and ensure that the methods used for the quantification of analyte in biological fluids are reliable, reproducible and suitable for its intended application. Different regulatory agencies like Food and Drug administration (FDA), The National Health Surveillance Agency or Agência Nacional de Vigilância Sanitária (ANVISA), European Medicines Evaluation Agency (EMA), Ministry of Health, Labor and Welfare (MHLW), International Conference on Harmonization (ICH) etc. provide guidelines for bioanalytical method validation. The present study provides an insight about the history of bioanalytical method validation including the details of various validation parameters and their description as per the different regulatory guidelines. The study also includes the parameters of ligand based assay methods and their description.