In 54 rheumatoid arthritis patients undergoing conventional chrysotherapy, we prospectively sought predictors of response, using strict clinical and laboratory criteria of improvement. Forty-five patients who completed 6-12 months of therapy were classified into 3 outcome categories: group 0, not significantly improved (18 patients); group 1, improved (18 patients); and group 2, markedly improved (9 patients). Sixty-two entry variables were tested in univariate and multivariate analysis for predictor function. No continuous variable was predictive. The discrete variables HLA-A3 positivity and HLA-DR4 negativity were the best predictors of response to gold. In a multivariate analysis using these 2 univariates (A3 and DR4) plus hemoglobin, we developed a discriminant function that correctly predicted outcome in 21 of 23 patients in groups 0 and 2. We also observed that of 15 DR blank patients (10 of whom were DR4 blank), none entered remission.