Methyclothiazide, a diuretic antihypertensive agent is a member of benzothiadiazine class of drug. It helps in prevent your body from absorbing too much salt which can cause fluid retention ,used to treat high blood pressure, fluid retention in people with congestive heart failure, Cirrhosis in liver, kidney problems or oedema caused by using steroids or estrogens. Along with its needful effects, Methyclothiazide causes some unwanted effects among which mostly are of unknown reason. Bio analysis helps to provide information about metabolic fate, pharmacokinetics of drugs and unknown facts of the drug. Hence a new HPLC-UV method has been developed using Inertsil ODS C18 column and Actonitrile and Methanol in 20:80 ratio as stationary phase and mobile phase for determination of Methyclothiazide in plasma using Ionic Liquid DLLME method. Novelty of the proposed method is extraction method used for sample preparation. Use of Ionic liquids as extraction solvent made the method environmentally friendly. Proposed method was accurate, precise, and robust. Matrixed calibrated standards were prepared and the developed method was linear over the range of 20-70 μg/ml. The percentage recovery for Quality controls was between 98%-102%. Hence the proposed method can be used for determination of Methyclothiazide in biological fluid.