The coordinated gold compound, 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranosato-S-triethylphosphine-gold (auranofin) was found to be effective in increasing the life span of C57BL x DBA/2 F1 mice inoculated with the lymphocytic leukemia P388. A number of dose schedules were used, the lowest dose being 6 mg/kg every fourth day and the highest dose being 6.0 mg/kg twice daily for 9 days; the lowest and highest doses produced treated versus control ratios of 140 and 220%, respectively. All treatment groups achieved the minimum treated versus control ratio of 125%. Animal weights remained stable at twice-daily and high-dose-daily regimens. Increased life span and weight changes were both found to correlate with drug concentration and/or dose frequency.