Anthelmintics were administered during processing at the Garden City Experiment Station. Four trials were conducted to evaluate the efficacy of: levamisole (boluses, cattle wormer pellets and injectable solution); and thiabendazole boluses. Levamisole hydrochloride injectable solution (18.2%) was administered at 2 cc/cwt. Levamisole wormer pellets were mixed with other ration ingredients at 0.1 lb./cwt. of animal body weight at the a.m. feeding and all of the mix was consumed within 4 hours. Some very meaningful conclusions can be made from these data. In general, rate of gain, feed efficiency and cost of gain were similar for both thiabendazole and levamisole. Therefore, an overall summary showing the percent improvement in performance obtained with anthelmintics (results composited for thiabendazole and levamisole) in four trials involving 936 stressed calves is shown in Table 7. In all perimeters shown here, the use of anthelmintics improved performance of stressed calves resulting in a substantial savings (9 .8 percent) in cost of gain. However, cost of gain data did not include death losses. In these trials, death losses were higher for calves that received levamisole (bolus or injectable) than for untreated animals. As noted earlier, death losses involved only a small percentage of the animals, so more data need to be obtained on death losses before conclusions can be drawn relating to death losses (if any) associated with anthelmintics.