This MiniReview describes the present guidelines for drug testing in forensic toxicology, workplace testing and doping control of athletes. Such guidelines are established to secure the chain of custody, from sample collection through analysis with screening, confirmation methods and interpretation, to the final report of results. Specifications for good laboratory practice, facility maintenance and quality assurance programs are described. The advantages and limitation of immunological drug assays and the necessity of specific chromatographic confirmation methods are discussed. The importance of correct interpretation of positive test results is illustrated. The effect of drug testing on the prevalence of drug abuse, accident rates and effectivity at the workplace is discussed.