The article deals with polarographic and voltammetric methods, both direct and indirect, in the study of morphine, codeine, heroin and their oxidation products, hydromorphone, hydrocodone, etc. Special attention is devoted to the morphine antagonist, naloxone, which is structurally related to morphine. Analytical use of electrochemical methods, their sensitivity and specificity as well as the reduction mechanism with regard to synthetic utilization are outlined. Electrochemical activity of apomorphine, another oxidation product of morphine, is discussed.