Tadalafil is classified as potent and highly selective phosphodiesterase type5 (PDE5) inhibitor that is used for treating erectile dysfunction (impotence) and pulmonary arterial hypertension. Present study was aimed to develop simple method for isolation and estimation of tadalafil from human plasma. A simple bioanalytical LC-UV method for estimation of tadalafil in human plasma by protein precipitation technique. Analyte was recovered from plasma by acetonitrile as a protein precipitating agent and subsequently separated on Phenomenex Luna C18 column (150X4.6 mm, 5µ) with security guard cartilage C18 using acetonitrile : water (45:55) as mobile phase at flow rate 1.0 ml/min at 286 nm. Tadalafil was eluted at 6.7 min. The calibration curve was linear (R2=0.999) over concentrations range of 0.25-5µg/ml in human plasma. The intraday and inter-day precision value were <15% and accuracy all within 15% (for LLOQ20%).