This study examined the factors that are related to collaboration between high school social workers and substance abuse prevention/intervention counselors in New York State high schools (except for New York City high schools). Constructs that were analyzed were high school social workers' perceived adequacy in working with high school students' substance abuse, social workers' estimation of the prevalence and severity of substance abuse problems in the schools, and knowledge that the social workers and drug prevention counselors have of each others' roles. Additional factors examined in relation to collaboration as seen in referrals, consultations and joint activities include years of experience, location, and size of school, job description, procedures for communication, gender and impact of mutuality of referrals between social workers and counselors. Questionnaires were sent to 352 high school social workers. Of the 130 social worker responses, 92 social workers had drug prevention programs in their schools and were analyzed for the study. Collaboration in the form of referrals and formal consultations between the two types of personnel was greater than anticipated. Findings also showed that suburban and rural schools experienced more collaboration between social workers and drug prevention counselors than did urban schools. Implications of study findings are discussed.