Purpose: To compare ultrasonography (US) with three-phase bone scintigraphy (BS) for detection of plantar fasciitis (PF). Materials and methods: Forty-three consecutive patients with a clinical diagnosis of PF were prospectively studied with US and BS. There were 58 symptomatic feet and 28 asymptomatic feet US positive findings for PF were thickness of the proximal plantar fascia> 3.9 mm (T) and hypoechoic fascia (H). Focal uptake at the medial calcaneus tuberosity in the early and delayed images were used as BS positive findings for PF. Receiver operating characteristic (ROC) methodology was used to analyze the results. Sensitivity, specificity, positive and negative predictive values, and accuracy in diagnosis of plantar fasciitis were calculated for both modalities. Results: The mean area under the ROC curve, indicating successful diagnosis of PF, was 81.6% for BS, 76.5% for T and 81.8% for H (P> 0.25). The sensitivities were 77.6%, 74.1% and 70.7%, respectively for BS, T, and H (P>0.39). The specificity of BS (85.7%) did not differ significantly from the specificity of H (92.9%, p=0.20). Plantar fascia thickness specificity (71.4%) was significantly lower than BS (P=0.038) and H (P=0.0000). There were no statistically significant differences between positive and negative predictive values. Also, in 10 patients (23%), other causes of foot pain were found by BS. Conclusion: US and BS demonstrate no statistically significant difference in ability to demonstrate plantar fasciitis in patients with heel pain. (C) 2000 Harcourt Publishers Ltd.