THE REPORT IS AN EDITED TRANSCRIPT OF PRESENTATIONS AND DISCUSSIONS THAT TOOK PLACE DURING THE MEETING, WHICH BROUGHT TOGETHER SOME 37 EXPERTS IN THE FIELD OF DRUG ABUSE EPIDEMIOLOGY. INCLUDED ARE AN OVERVIEW OF THE CONFERENCE, PLUS SECTIONS ON ISSUES, METHODOLOGY, AND FUTURE DIRECTIONS. AMONG THE ISSUES CONSIDERED ARE THE STATUS OF OPERATIONAL DEFINITIONS IN THE FIELD OF DRUG ABUSE, THE CONCEPT OF 'POLYDRUG USE,' AND THE QUESTION OF WHETHER EPIDEMIOLOGICAL STATISTICS CAN ACTUALLY HELP AMELIORATE DRUG ABUSE. METHODOLOGICAL PAPERS ON DATA ACQUISITION TOUCH ON THE FOLLOWING TOPICS: PROBLEMS OF ACHIEVING HIGH RATES OF RETURN AND PREVENTING BIAS; PROBLEMS IN LONGITUDINAL STUDIES (SAMPLE ATTRITION, INTERPRETATION OF CHANGES, PROTECTION OF HUMAN SUBJECTS); OBSERVATION OF DRUG USERS ON THE STREET AS A MEANS OF ESTIMATING THE EXTENT AND NATURE OF DRUG ABUSE; DRUG ARRESTS AS A SOURCE OF EPIDEMIOLOGICAL STATISTICS; USING STREET BUYS TO ASSESS DRUG EPIDEMICS; DESIGNING STUDIES OF TREATMENT POPULATIONS; FINDINGS FROM A STUDY OF DRUG-RELATED DEATHS IN MAJOR CITIES; A HOSPITAL-BASED NETWORK OF INFORMATION ON DRUG ABUSERS; THE UTILITY OF SERUM HEPATITIS DATA FOR ESTIMATING DRUG ABUSE TRENDS; AND THE ACCURACY OF URINANALYSIS DATA IN SCREENING OR MONITORING DRUG ABUSE. OTHER PAPERS DESCRIBE PROBLEMS IN APPLYING AND EXTRAPOLATING DATA ON DRUG ABUSE. A SUMMARY OF MAJOR DRUG ABUSE TRENDS BASED ON STATE SURVEYS IS PRESENTED AS AN EXAMPLE OF THE PRODUCT OF EPIDEMIOLOGICAL RESEARCH. RECOMMENDATIONS FOR IMPROVING SUCH RESEARCH INCLUDE CLOSER COLLABORATION BETWEEN DRUG ABUSE AND MENTAL HEALTH EPIDEMIOLOGISTS, MERGING OF INFORMATION ON ALCOHOL USE AND DRUG ABUSE FOR GREATER INSIGHT INTO SUBSTANCE ABUSE TRENDS, AND MORE LONGITUDINAL SURVEYS OF DRUG ABUSE. ALSO INCLUDED IS INFORMATION ON GOVERNMENT SPONSORSHIP OF EPIDEMIOLOGICAL RESEARCH IN DRUG ABUSE. SUPPORTING DATA AND LISTS OF REFERENCES ARE PROVIDED. (LKM)