Plantar fasciitis (FP) is a frequent and disabling condition that can be treated with focused extracorporeal shock waves.The main objective of this study was to assess the effectiveness of focused extracorporeal shockwave treatment in FP according to the energy density used.Eighty-two patients with a clinical diagnosis of FP were included and assigned, by simple random sampling, to two treatment groups: medium-high energy density (0.59mJ/mm2) and medium-low energy density (0.27mJ/mm2).Pain and functionality were assessed using the VAS (Visual Analogical Scale) and AOFAS (American Orthopedic Foot and Ankle Society Ankle-Hindfoot Scale) scales, respectively, at the start of the study (baseline consultation), and at the first, third and sixth month post-treatment.Finally, the degree of patient satisfaction was evaluated using the Roles and Maudsley score.The results of the scales in the post-treatment reviews were compared, and statistical significance was obtained for the main study variables (pain and functionality) in each intervention group.Although pain levels and functionality improved in both study groups after treatment, a greater and earlier analgesic and functional response was obtained for the medium-high energy density group.