This study compared the nauseogenicity of two different strategies for exploring virtual environments whilst wearing an immersive head-mounted display. In the first, the head was kept still and movement was achieved solely by manipulating a hand-control. In the second, the subject was free (and encouraged) to move his or her head when exploring the virtual world. Fourteen subjects completed both of the 20 min trials, three further subjects withdrew from the study after one trial. Subjects reported increases in adverse symptoms when using each strategy and, for the group as a whole, nausea increased steadily during each immersion period. However, significantly larger changes were reported when the head moved than when it was still, as predicted from sensory conflict theory.