STUDY DESIGN:Randomized clinical trial. BACKGROUND:Plantar heel pain is a common foot complaint that causes significant disability and poorer health-related quality of life. Foot orthoses and corticosteroid injection are effective treatments for plantar heel pain, however it is unclear if one is more effective than the other. Therefore, the aim of this trial was to compare the effectiveness of foot orthoses and corticosteroid injection for plantar heel pain. METHODS:A parallel-group, assessor-blinded randomized trial. Participants received prefabricated, arch-contouring foot orthoses or a single ultrasound-guided corticosteroid injection. The primary outcome measure was the foot pain subscale of the Foot Health Status Questionnaire at 4 and 12 weeks. RESULTS:103 participants aged 21 to 72 years (63 female) with plantar heel pain were recruited from the community and received an intervention. For the primary outcome of foot pain, corticosteroid injection was more effective at week 4 (adjusted mean difference 8.2 points; 95% CI 0.6, 15.8). However, foot orthoses were more effective at week 12 (adjusted mean difference 8.5 points; 95% CI 0.2, 16.8). Although these findings were statistically significant, they did not meet the previously calculated minimal important difference value of 12.5 points. CONCLUSION:Corticosteroid injection is more effective than foot orthoses at week 4, but this effect does not last, and appropriately contoured foot orthoses are more effective than corticosteroid injection at week 12. However, patients may not notice a clinically worthwhile difference between the interventions. LEVEL OF EVIDENCE:Therapy, level 1b. J Orthop Sports Phys Ther, Epub 26 May 2019. doi:10.2519/jospt.2019.8807.