A cost-utility analysis within a randomized controlled trial was conducted from the health care perspective.The aim of this study was to determine whether individualized physical therapy incorporating advice is cost-effective relative to guideline-based advice alone for people with low back pain and/or referred leg pain (≥6 weeks, ≤6 months duration of symptoms).Low back disorders are a burdensome and costly condition across the world. Cost-effective treatments are needed to address the global burden attributable to this condition.Three hundred participants were randomly allocated to receive either two sessions of guideline-based advice alone (n = 144), or 10 sessions of individualized physical therapy targeting pathoanatomical, psychosocial and neurophysiological factors, and incorporating advice (n = 156). Data relating to health care costs, health benefits (EuroQol-5D) and work absence were obtained from participants via questionnaires at 5, 10, 26, and 52-week follow-ups.Total health care costs were similar for both groups: mean difference $27.03 [95% confidence interval (95% CI): -200.29 to 254.35]. Health benefits across the 12-month follow-up were significantly greater with individualized physical therapy: incremental quality-adjusted life years = 0.06 (95% CI: 0.02-0.10). The incremental cost-effectiveness ratio was $422 per quality-adjusted life year gained. The probability that individualized physical therapy was cost-effective reached 90% at a willingness-to-pay threshold of $36,000. A saving of $1995.51 (95% CI: 143.98-3847.03) per worker in income was realized in the individualized physical therapy group relative to the advice group. Sensitivity and subgroup analyses all revealed a dominant position for individualized physical therapy; hence, the base case analysis was the most conservative.Ten sessions of individualized physical therapy incorporating advice is cost-effective compared with two sessions of guideline-based advice alone for people with low back disorders.2.