The prevalence of drug abuse among homeless people in New Haven, Connecticut, was examined using questionnaire data collected from 80 percent of all homeless persons (N= 181) residing in the city's five emergency shelters during a four-week study period in 1990. Fifty-four percent of the sample had used drugs during the 30 days before the interview, and almost two-thirds during the previous year. Cocaine was reported to be the most frequently used drug. Almost one-fourth of the sample identified drug use as the primary reason for their homelessness. Drug use was most prevalent among people who had been homeless for six months to three years and less prevalent among newly homeless people and people who had been homeless four years or more.