BACKGROUND: Plantar heel pain can be managed with dry needling of myofascial trigger points; however, there is only poor-quality evidence supporting its use. OBJECTIVE: The purpose of this study was to evaluate the effectiveness of dry needling for plantar heel pain. DESIGN: The study was a parallel-group, participant-blinded, randomized controlled trial. SETTING: The study was conducted in a university health sciences clinic. PATIENTS: Study participants were 84 patients with plantar heel pain of at least 1 month's duration. INTERVENTION: Participants were randomly assigned to receive real or sham trigger point dry needling. The intervention consisted of 1 treatment per week for 6 weeks. Participants were followed for 12 weeks. MEASUREMENTS: Primary outcome measures included first-step pain, as measured with a visual analog scale (VAS), and foot pain, as measured with the pain subscale of the Foot Health Status Questionnaire (FHSQ). The primary end point for predicting the effectiveness of dry needling for plantar heel pain was 6 weeks. RESULTS: At the primary end point, significant effects favored real dry needling over sham dry needling for pain (adjusted mean difference: VAS first-step pain=-14.4 mm, 95% confidence interval [95% CI]=-23.5 to -5.2; FHSQ foot pain=10.0 points, 95% CI=1.0 to 19.1), although the between-group difference was lower than the minimal important difference. The number needed to treat at 6 weeks was 4 (95% CI=2 to 12). The frequency of minor transitory adverse events was significantly greater in the real dry needling group (70 real dry needling appointments [32%] compared with only 1 sham dry needling appointment [<1%]). LIMITATIONS: It was not possible to blind the therapist. CONCLUSION: Dry needling provided statistically significant reductions in plantar heel pain, but the magnitude of this effect should be considered against the frequency of minor transitory adverse events.