A simple and gradient RP- HPLC method has been validated and developed for Entecavir in bulk and tablet dosage form. The proposed method was validated to obtain official requirements including stability, accuracy, precision, linearity and selectivity. The method was developed on C18 column (250 x 4.6 mm ID) using the mobile phase composition as methanol: water (55:45 v/v). The flow rate was set as 1ml/minute and the maximum absorption was observed at 254 nm. The Entecavir drug showed a precise and good linearity at the concentration ranges of 5-25 µg/ml. The RP-HPLC, assay showed the highest purity ranging from 98.79 % to 99.91 % for Entecavir tablet formulation and 99.22 % was the mean percentage purity. The Entecavir retention time was found to be 3.5 minutes. The method accuracy was showed by statistical analysis. The developed RP-HPLC method can be utilized for the regular analysis of Entecavir in bulk and pharmaceutical dosage types in quality control laboratories. The proposed method was validated based on the ICH guidelines.