One of the cognitive symptoms associated with the diagnosis of a mild traumatic brain injury (mTBI) is the degradation of focus and attention. This pilot study was designed to quantify examples of such capabilities in Service Members diagnosed with mTBI and to compare their abilities to peers without an mTBI diagnosis. Specifically, we compared participant groups on their false alarm rates and thresholds for contralateral and informational masking tasks to document the participants' ability to focus and detect an auditory stimulus in the presence of distracting maskers. In this study, comparing the overall performance of Service Members, with and without a mTBI, did not yield significant group differences but did highlight the considerable variability associated with mTBI. The Service Members' data were then compared to data from a group of civilian adults of a similar age whose data were previously published in two doctoral dissertations. This comparison found significant group differences, with the Service Members performing worse than the group of civilian adults, in informational and contralateral masking. Later work may incorporate subjective as well as objective measures to investigate the participants' reported deficits and how they relate to behavioral responses.