Student fieldwork and service learning are valuable strategies for developing the skills of future public health professionals. Practitioners who serve as preceptors to students often receive little preparation for guiding and evaluating students. Findings from a review of fieldwork and service learning literature and a program evaluation of an undergraduate public health program at a large southern public university were used to construct guidelines for the practitioners supervising students in the field. These guidelines should aid practitioners in their role as preceptors of public health students. The guidelines address assessing student competencies, developing student competencies, writing learning objectives, evaluating students, maximizing the student precept or relationship, and managing problems.