Many methods of social work practice, including brokering, case advocacy, and cause advocacy, require the social worker to engage in negotiations to resolve disputes. This article demonstrates how principled negotiation, a form of negotiating developed out of the Harvard Negotiation Project at Harvard University and used widely in the business and legal world, can be an effective tool in social work practice. Principled negotiation is especially consonant with the value base of social work because it strives for the just and mutually beneficial resolution of conflicts while acknowledging the value and importance of ongoing relationships. A case example applying the rules of principled negotiation is described in the context of case advocacy. Its application to other social work practice methods is also examined.