Orthotic devices have a multitude of applications. To properly prescribe them, one must have a clear understanding of the biomechanics of the lower limbs. These devices can support, correct, and prevent many pathologic conditions. The author has had experience with 235 patients, utilizing stance-phase, molded, thermoplastic orthotic devices. One hundred seventy-six patients responded to a questionnaire. Almost 80% of the patients experienced at least 50% improvement of their symptoms. With careful analysis, these devices not only can improve lower-segment malalignment syndromes in the athletic population but can also give relief to the patient with a painful foot and prevent serious ulcerations in the diabetic or rheumatoid patient.