Practice guidelines are promoted as an important means of achieving high-quality, cost-effective health care. Nurse practitioners must understand what practice guidelines are and how they are developed and be willing to put them into practice. This discussion begins with a description of practice guidelines specific to pediatrics. The terminology used in reference to these "clinical tools" are differentiated and their historic and contemporary influences are summarized. The complexity of guideline development and attributes of a quality practice guideline are described. Finally, the pivotal roles nurse practitioners can play in putting guidelines into practice are suggested.