Low back pain (LBP) is a pandemic and costly musculoskeletal condition in the United States. Patients with LBP may endure surgery, injections, and expensive visits to emergency departments. Some suggest that using physical therapy or chiropractic in the earlier stage of LBP reduces the utilization of expensive health services and lowers the treatment costs. Nevertheless, there is no consistent evidence to declare which one of these methods is a cost-effective treatment within a short (less than a year) period of time. The purpose of this study was to investigate the cost-effectiveness of chiropractic versus physical therapy in the United States. A decision tree analytic model was used for estimating the economic outcomes. The findings showed that in the chiropractic group, the total average cost was $48.56 lower than the physical therapy group, and daily adjusted life years (DALY) was 0.0043 higher than the physical therapy group. Chiropractic care was shown to be a cost-effective alternative compared with physical therapy for adults with at least three weeks of low back pain over six months.