Method development is an integral part of drug development process. Bioanalysis plays a significant role in evaluation and interpretation of bioavailability, bioequivalence, pharmacokinetic and toxicokinetic studies. Bioanalytical methods employing LC-MS/MS allow the analyte of interest in highly complex mixtures to be isolated and measured. Baclofen is a skeletal muscle relaxant used to treat pain and certain types of spasticity from multiple sclerosis, spinal cord injuries, or other spinal cord diseases. A simple and a rapid LC-MS/MS method has been developed and validated for the estimation of baclofen in human plasma using baclofen D4 as an internal standard. The analysis was performed on Shimadzu HPLC combined with Applied Biosystems API 4000 mass spectrometer using turbo spray ionisation mode. Sample preparation was accomplished by solid phase extraction technique. Chromatography was carried on Hypurity C18 column, 100x4.6mm, 5µ using a mobile phase consisting of acetonitrile: 10 mM ammonium acetate (80:20 v/v). Baclofen and baclofen D4 eluted at 1.50 min (±0.50 min) with an overall run time of 3 minutes. Linearity was established over a concentration range of 1.018 to 504.12 ng/ml for baclofen. The method was validated as per EMA guidelines and the results were found to be within acceptable limits.