An impressive array of scientific papers has been published in peer-reviewed literature over the intervening 80 years since the first documented results of breath alcohol testing. This array has clearly demonstrated the soundness and validity of measuring blood alcohol concentration by means of breath samples when the testing is performed in accordance with sound scientific practices. There has been criticism of this process, especially when proper protocols and procedures are not followed or are simply ignored in given testing situations. However, the criticism for the most part is directed toward the administration of the breath test, not the scientific basis for breath testing for alcohol. The successful prosecution of drinking drivers under statutory limit laws ultimately must depend on scientifically sound results to prove the blood alcohol concentration of the offending driver. Instruments must meet all of the four basic elements of accuracy, precision, reliability, and specificity; like Canada, every country that embarks on evidential breath alcohol analysis subjects these instruments to rigorous evaluation standards of the four basic elements. Moreover, to achieve scientifically sound results in operational use, user agencies must ensure that approved instruments are operated by qualified personnel using procedures based on good laboratory practice. The Canadian Society of Forensic Science Alcohol Test Committee has identified and provided a set of procedures that are necessary for the correct operation of approved instruments. These procedures should ensure that test results are scientifically sound in accordance with the principles of good laboratory practice. Bibliography