From August 1986 to July 1989, 98 patients receiving primary cadaveric kidney transplants received either RATS (n = 50) or MALG (n = 48) during the induction phase of a quadruple immunosuppressive protocol. Patient groups were well matched. The duration of RATS and MALG treatment and the time of CyA induction were equivalent. Serum creatinine and rejection episodes up to 1 year were not statistically different. Hematologic side effects resulted in dose reduction of MALG in 42% of patients without adverse rejection results. In the RATS group, no dosage reductions were required. One-year patient survivals (96% to 100%), and 1-year graft survival (82% to 85%) were not significantly different in the 2 groups. Infectious complications were 30% higher in the MALG group and a significant factor in 2 deaths. Monitoring of lymphocyte subsets revealed insignificant differences in the percent of decrease of each cell population between MALG and RATS groups during induction.