The abuse of addictive drugs has been increasing world-wide and causing serious social problems. The development and application of analytical methods of the abused drugs in biological specimens are very important for the prediction of and protection from the risk to human health. Drugs of abuse that are most commonly tested include alcohol, amphetamines, cannabinoids, cocaine, opiates, and phencyclidine The biological specimens such as urine, blood and hair have been used for elucidation of the use of addictive drugs. Commonly employed testing methods include immunoassay and chromatography. Testing methods vary in their sensitivity, specificity, time, and cost. In this review, basic knowledge about drugs of abuse, kinds of specimen, methods for their analytical determination, possibilities and limitations of interpretation of the analytical result are discussed.