Two experiments were conducted to evaluate the effects and interactions of dietary levels of corn oil (0 vs 6%) and dried whey (0 vs 25%) on performance of young pigs during a 4-wk postweaning period. The first experiment, conducted in five replicates as a 2 x 2 factorial in a randomized block design, evaluated gain and feed intakes of 172 pigs weaned at 21 d of age. Pigs were bled at weekly intervals, and samples were assayed for serum triglyceride and urea concentrations. In a second experiment, 36 barrows in three replicates were used to evaluate the same treatments on apparent digestibility and absorption of fat and N retention during each week of a 4-wk postweaning period. The dietary inclusion of dried whey resulted in greater gains and feed intakes and reduced feed-to-gain ratios during each week of the postweaning period, with the largest relative improvement occurring during wk 1. Supplemental corn oil did not enhance pig gains the first 3 wk postweaning, but response improved by wk 4. Feed intakes were slightly (P less than .10) lower when corn oil was provided. The inclusion of corn oil resulted in an improved feed-to-gain ratio (P less than .01), particularly evident during wk 3 and 4 postweaning. Neither gain nor feed utilization were improved by added corn oil during the initial 2-wk postweaning period regardless of dried whey addition. Apparent digestibilities of fat were unaffected at each weekly interval by dietary dried whey inclusion.(ABSTRACT TRUNCATED AT 250 WORDS)