BACKGROUND: Motion control and comfort are primary objectives in orthotic intervention. Semicustom orthotic devices have been presented as a more cost-effective solution than custom orthotic devices. However, no studies have compared their function or comfort to that of custom orthotic devices. METHODS: Nineteen uninjured runners were fitted for custom and semicustom orthotic devices. Subjects underwent an instrumented gait analysis of running and walking in no-orthotic, custom orthotic, and semicustom orthotic conditions. Subjects completed visual analog scales for the custom and semicustom orthotic conditions. One-way repeated measures analyses of variance were performed on the rearfoot variables of peak eversion, eversion excursion, eversion duration, and eversion velocity. Two-tailed, dependent t tests were used to compare comfort. RESULTS: Eversion excursion showed significant differences between the conditions: during running, it was reduced in the custom orthotic as compared to the no-orthotic condition; during walking, it was reduced in the semicustom orthotic as compared to both the custom and no-orthotic conditions. The custom orthotic devices were significantly more comfortable (P < .05) than the semicustom devices in the area of the edges only. CONCLUSION: The results suggest that, in uninjured individuals, there are few differences in rearfoot motion control and comfort between the custom and semicustom orthotic devices used in this study.