This paper examines the theoretical position of the person who drops out of illegal drug use. A person was considered a drop-out if he admittedly no longer used any or all the drugs in the following categories: marijuana, hallucinogens, speed, downers, and inhalants. A purposive sample was drawn to capture as many people fitting this criterion as possible. Two hundred and fifty non-institutionalized subjects were contacted and interviewed. Some major quitting contingencies which appear to act across all drug categories are: the early or late occurrence of bad mental or physical experiences on drugs, geographic mobility away from the drug scene, the gradual development of meditation as a substitute for drug use, an abrupt conversion to Christianity at the height of one's career, negative social pressure from significant or more generalized others, and the widespread tendency to "burn out" or simply lose interest after long term use of street drugs. Patterns specific to each type of drug are also discussed. (Author/NMF)