The objective of this study was to compare pediatricians, family practitioners, and internist's adherence rates to an individual practice association-developed otitis media practice guideline. The study included a cohort of primary care physicians treating acute otitis media between January 1, 1999, and December 31, 2001, using administrative data. All panel pediatricians, family practitioners, and internists were included in the analysis. Specialty otitis media guideline adherence rates were compared pre- and postintervention. The guideline was adapted from the 1999 Centers for Disease Control and Prevention's treatment recommendations. The outcome measure was overall and specific exceptions to practice guideline components prior to and after intervention per 1000 episodes. Pediatricians and internists significantly reduced overall exceptions per 1000 episodes (P < .000) from the pre- to postintervention periods. Family practitioners did not improve adherence to overall guideline recommendations postintervention (P > .05). Pediatricians had significantly higher compliance than did family practitioners (P < .000). Primary care physicians significantly increased adherence to an otitis media guideline. Pediatricians improved more than internists and significantly more than family physicians.