A prospective 24 week study of 31 patients with active rheumatoid arthritis (18 women, 13 men) was undertaken to determine whether weekly intramuscular sodium aurothiomalate (gold) would influence delayed type cutaneous hypersensitivity (DTH) and other indices of cell mediated immunity. DTH to seven recall antigens was measured by Multitest on three occasions during the study. Twenty five patients completed the study. At entry 13 patients (12 female) were anergic, and no significant correlations were found between DTH and other clinical and immunological indices. Women showed a significantly greater depression of DTH than men. At week 24 only three of the patients were anergic with significant increase in mean DTH score being noted particularly to tuberculin, candida, and streptococcus. Improvement in DTH was observed in both gold responders and non-responders. In conclusion, patients with active rheumatoid arthritis show impairment of DTH, which is reversed by chrysotherapy. This effect is most apparent in women and appears to be relatively independent of the clinical response.