In conjunction with six Maryland telephone crisis hotlines, the Center for Substance Abuse Research has developed MAHRS. A scannable telephone log form was developed to meet data- collection needs of each hotline. The hotlines agreed to ask several drug-related questions of all callers who mention alcohol or drugs as a problem. Completed forms are sent to the Center for Substance Abuse Research each month for optical scanning and analysis. Based on the first 5 months of MAHRS data collection (March 1-July 31, 1993), approximately 10 percent of calls to the six hotlines involve alcohol or other drugs (AOD). The monthly number of AOD-related calls was stable over the period, which suggests that calls to MAHRS hotlines are a promising indicator of community-level drug problems. More than half of the callers who mentioned alcohol and/or other drugs as a problem reported a current need for treatment, which lends credibility to MAHRS as a needs-assessment and treatment-planning tool. One-third of the AOD-related calls resulted in referrals to addiction services. The AOD-related problems mentioned by hotline callers are consistent with what is known from other sources about patterns of drug use in the State. A comparison of MAHRS data and data from the Substance Abuse Management Information System, an established indicator of substance use and treatment use, also shows agreement regarding the regional distribution of substance use. 15 tables, 4 figures, appended methodological and administrative considerations, and 8 references