The ability to inhibit a prepotent motor response has been shown to be impaired in a number of disorders that are characterized in part by impulsive behavior. While impulsivity is a ubiquitous feature of bipolar disorder (BPD), little research has explored motor inhibition in this population. Further, because a successfully inhibited response is a non-observable event, the assessment of motor inhibition ability requires specialized tools. The Stop signal task, a computer administered task requiring the participant to inhibit a prepotent motor response, allows for the parsing of response behavior into measures of discrimination reaction time and inhibition ability (stop latency). In the current study, we administered the Stop signal task to 26 asyndromal individuals with BPD and 24 demographically matched healthy volunteers. It was hypothesized that individuals with BPD would demonstrate slower stop latencies as compared to healthy volunteers. Further, because other studies have reported a link between cognitive impairment and psychiatric symptomatology, it was hypothesized that subsyndromal symptoms would adversely impact inhibition performance. The results from the current study failed to support either of the hypotheses. However, individuals with BPD demonstrated slower reaction times than the healthy volunteers, and, the BPD group became increasingly more variable in their reaction times and also made increasingly more errors of omission as the experiment progressed. Taken together, the results of this study suggest that simple motor inhibition is intact in asyndromal individuals with BPD. In contrast, the slow response times, increased variability, and increased omission errors are suggestive of impaired vigilance as well as impaired information processing abilities.