The purpose of this study was to examine differences in performance and postural sway among individuals performing a task when using and not using a head-mounted display (HMD). Twenty participants completed a repeated measures study in which they performed a simple object location targeting task while using and not using an HMD. Accuracy, time-to-hit, and postural sway were measured. Significant differences in accuracy and time-to-hit were found, indicating participants’ task performance was worse while using the HMD. Significant differences in magnitude of postural sway were found in elliptical area and path length, showing more sway when using the HMD than when not using it. These methods can be used to objectively measure user differences in response to wearing and using an HMD that can result in negative effects for users.