||Different regulatory bodies have different approach towards validation of bio-analytical method. Parameters to be performed for validation are almost same, however procedure or how to perform is somewhat different. The current regulatory guidelines issued by different regulatory agencies for the bio-analytical method validation are- 1. USFDA-2001, Draft guidance-Sept 2013(for small molecules and ligand-binding assay), 2-EMEA-2012(for small molecules and ligand- binding assay), 3-ANVISA (Re 899, RDC 27, 2012). The present review compares and summarizes these regulatory guidelines. This review also discusses evaluation of validation parameters such as selectivity, carry over effect, matrix effect, precision and accuracy, dilution integrity, various stability aspects.