AbstractThis article reports a study of referrals among social service and mental health agencies. Staff from human service agencies were interviewed about the process of referring and asked to make simulated referrals using mock clients constructed for this study. Interview data show lack of communication and inappropriate referrals as the biggest problems with the referral system. Interjudge agreement about the simulated referral choices was found to be not significantly different from chance. The data also suggest that agency staff refer on the basis of “habits” as much or more than on the basis of client problems. The frequency of inappropriate simulated referrals was relatively high (15%) considering that agencies included in the sample are large public agencies with broad definitions of what clients are appropriate for their services. Implications of these findings are discussed in terms of existing incentives for agencies to cooperate or compete and need for methodology to evaluate service delivery systems or netwo