The ultimate goal of medication use is to attain the optimum therapeutic benefits or outcomes for the improvement of the patient's quality of life. About 30% of medical problems that are occurring in hospitals are related to medication errors which are preventable and harming at least 1.5 million people every year. To evaluate and categorize the medication errors that occurred in hospitalized patients of tertiary care hospital, Vijayawada, Andhra Pradesh to improve the patient treatment outcomes. The prospective observational study was carried out in the in-hospitalized patients of tertiary care hospitalsfrom June 2018 to November 2018. Out of 400 prescriptions, medication errors were found in 66 cases, which counted to a total of 80 medication errors, the most frequently occurring medication error was wrong dose error (36, 40%), wrong drug error (14, 17.5%), wrong frequency error (10, 12.5%),omission error (4, 5%)dispensing error(4,5%), wrong route of administration (2,2.5%),wrong dosage form error(2,2.5%)monitoring error(2,2.5%)High incidence of medication error falls under the category Prescribing error(58,72.5%). Out of 80 ME'S high incidence of medication errors falls under the Category C(47.5%) followed by Category A(15%),Category E(15%),Category F(10%), Category B(7.5%),Category D(5%).This may be due to an environment that is susceptible to medication errors. The study concluded that the high incidence of medication error occurred in the Neurology department (25%), followed by the Gastroenterology department (22.5%). The majority of errors that occurred to the patients did not cause any harm. There is a need to set up a ME detailing framework by Clinical Pharmacists to diminish its frequency and improve tolerant of patient consideration and safety.