Tea, is the most extensively used non-alcoholic caffeinated beverage in society today. A biosensor was created by immobilising urease enzyme on a nylon membrane and attaching it to an ammonium ion selective electrode (AISE). The enzyme electrode was characterized by Fourier transform infra-reds pectroscopy (FTIR) and Field emission scanning electron microscopy (FESEM) techniques with particle size ranging between 0.09µm-0.49µm.in diameter. The biosensor showed optimum response within 20s at pH 5.5 in 0.05mM urea conc. in sodium phosphate buffer and 40˚C. It exhibited excellent sensitivity of 38 mV/decade and lower detection limit is 0.001 mM, and wider linear range from 0.001 to 0.80 mM. Analytical recovery of added urea which were found to be 99.8%, 101.04%, 108.35%, 103.9%, 98.99%, 104.7%, 99.93%, 102.34%, 101.76%, and 103.02%. The average urea content for green tea was found to be approximately 130.57 mg/L whereas for tea it was approximately 122.93 mg/L. These findings could be beneficial for the health of the consumers.