This study’s objective was to compare knowledge in managing low back pain (LBP) between physical therapists and family practice physicians. Fifty-four physical therapists and 130 family practice physicians currently serving in the U.S. Air Force completed standardized examinations assessing knowledge, attitudes, the usefulness of clinical practice guidelines, and management strategies for patients with LBP. Beliefs of physical therapists and family practice physicians about LBP were compared using relative risks and independent t tests. Scores related to knowledge, attitudes, and the usefulness of clinical practice guidelines were generally comparable between the groups. However, there was a greater likelihood that physical therapists would recommend the correct drug treatments for patients with acute LBP compared to family practice physicians (85.2% vs. 68.5%; relative risk: 1.24 [95% confidence interval: 1.06-1.46]) and believe that patient encouragement and explanation is important (75.9% vs. 56.2%; relative risk: 1.35 [95% confidence interval: 1.09-1.67]). In addition, physical therapists displayed significantly greater knowledge regarding optimal management strategies for patients with LBP in comparison to family practice physicians. This study’s results may have implications for health policy decisions regarding the utilization of physical therapists to provide care for individuals with LBP without a referral.