Differential item functioning (DIF) is present when examinees who have the same level of a trait have a different probability of correctly answering a test item intended to measure that trait (Shepard & Averill, 1981). The following study is a DIF analysis of the Herrmann Brain Dominance Instrument (HBDI), a preference profiling instrument developed by Herrmann International to help individuals identify their dominant preferences and then classify their level of dominance into four preference quadrants. Examinees who completed the American English version of the instrument were classified as the reference group and examinees of the International English version were classified as the focal group. Out of 105 items, 11 were manifesting a large amount of DIF and were flagged for further review. The POLYSIBTEST procedure was used to carry out the DIF analysis. POLYSIBTEST is an extension of the SIBTEST procedure, which is a conceptually simple method for analyzing DIF that uses a latent trait measure rather than an observed total score. The latent trait measure helps detect both uniform and nonuniform DIF and the POLYSIBTEST procedure is used for both dichotomous and polytomous items. Each of the four preference quadrants were analyzed separately to reduce incorrect findings as a result of ipsative scoring. The process used to complete the DIF analysis was documented so that additional language groups may be analyzed by Herrmann International.