Drunken drivers in India always pose a high risk to other users of the roads. Nearly 0.14 million people lost their lives every year in last three years in India, which is more than all casualties of wars of India [6]. Statistics derived from postmortem reports from road traffic fatalities in various countries show that 20-50% of drivers had been drinking alcohol before the crash and level of consumed alcohol in their body was above the legal limit for driving [2,3]. The influence of alcohol or drugs, many a times, goes to the extent that driver becomes incapable of having control of vehicle leading to the ill fate [2,3]. Seeing the intensity of the matter, Government of India amended the relevant laws from time to time to make it more stringent to deter the offenders. The Motor Vehicle (Amendment) Bill 2016 is such an effort by the Government of India, which was approved by the Union Cabinet of India on 3rd of August 2016 [7]. Such cases, when passes through the process of Criminal Justice Delivery System, the quantity of ethanol determined by a forensic chemist in blood sample of the accused plays a vital role in fair trial. There are several methods available for determination of quantity of ethanol in blood and urine samples. Two such methods were used for ethanol determination in blood and urine samples by the authors. The objective of this paper is to describe the preferential selection of one method over the other in some cases and inclusion of the value of uncertainty of measurement while reporting the result. The available blood and urine samples were analyzed to determine the ethanol contents with the help of two methods. The contents of ethanol determined with two methods were found different to the extent of about 20 to 30 mg%. The results of the method with lower values were found justified with the case history and were reported along with inclusion of value of uncertainty of measurement.