Enzyme based sensor for detection of urea in milk was constructed using a piezo-electric sensor, which measures the pressure of the gas, evolved in the sample. The sensor showed linear behavior for varying concentrations of urea in the samples. The time response of the sensor was evaluated and liquid to gas ratio of 1:2.5 was found to give satisfactory output by the sensor. The results indicate that this technique can be effectively used to detect urea levels in milk. © 2005 Taylor and Francis Group, LLC.