Approximately 13% of 654 Reserve Component Gulf War veterans (18% women, 65% ground forces, between 24 and 61 years of age, average 40.2 yr.) surveyed in the Ohio Desert Storm Research Project reported that they had probably been exposed to nerve or mustard gas agents, while another 32% thought such exposures were possible. Reports of exposure were found, through ordinary least squares regression analysis, to be associated with membership in ground forces (Army/Marine Corps) (b = .29), geographical location (b = .17), ethnic minority status (b = .07), education (b = -.10), intrinsic religiosity (b = .10), and also reporting having had physiological reactions to vaccines or pyridostigmine bromide pills (b = .24). Reports were not associated significantly with subjective health before the war, age, or sex.