THREE BASIC RESEARCH QUESTIONS WERE ADDRESSED: (1) WHAT WAS THE ROLE OF SUBSTANCE USE, IF ANY, IN BECOMING A PROSTITUTE; (2) WHAT WERE THE FUNCTIONS AND DYSFUNCTIONS OF SUBSTANCE USE FOR PROSTITUTES; AND (3) HOW DID THE NATURE AND SCOPE OF SUBSTANCE USE SERVE TO SOCIALLY DIFFERENTIATE THE SUBCULTURE OF PROSTITUTION? THIS STUDY EMPLOYED QUOTA SAMPLING, OBTAINING DATA THROUGH INTERVIEWS. IT WAS FOUND THAT CERTAIN DRUGS WERE CLEARLY ASSOCIATED WITH PROSTITUTION. HOWEVER, DIFFERENT DRUGS WERE FOUND TO BE ASSOCIATED WITH DIFFERENT CLASSES OF PROSTITUTION. HEROIN WAS THE DRUG MOST CLEARLY ASSOCIATED WITH LOW-LEVEL PROSTITUTION, WHILE STIMULANTS WERE FREQUENTLY USED BY HIGH-CLASS PROSTITUTES. THE RELATIONSHIP BETWEEN PROSTITUTION AND ADDICTION WAS ALSO FOUND TO VARY DEPENDING UPON THE LEVEL OF PROSTITUTION. AMONG LOW-CLASS PROSTITUTES, ADDICTION TENDED TO PREDATE PROSTITUTION AND THE CAUSAL CONNECTION BETWEEN ADDICTION AND PROSTITUTION WAS MOST LIKELY TO BE ECONOMIC NECESSITY. AMONG HIGH-CLASS CALL GIRLS, PROSTITUTION WAS MOST LIKELY TO PREDATE ADDICTION AND THE CAUSAL LINKAGE TENDED TO BE ROOTED IN THE PSYCHOACTIVE FUNCTIONS OF THE DRUG. IN ADDITION, SUBSTANCE USE WAS SHOWN TO BE RELATED TO ENTRY INTO PROSTITUTION IN FOUR DIFFERENT WAYS: (1) ECONOMIC, (2) PSYCHOACTIVE, (3) FUNCTIONAL, AND (4) SUBCULTURAL. IT IS CONCLUDED THAT THE USE OF DRUGS BY PROSTITUTES APPEARS TO BE AND INDICATOR OF THEIR ADAPTATION AND COMMITMENT TO A DEVIANT SOCIAL ROLE. TABLES, DATA COLLECTION INSTRUMENTS, AND LIST OF REFERENCES ARE PROVIDED. (AUTHOR ABSTRACT MODIFIED-MLC)