The aim of this study was to evaluate the effects of Cr supplementation (as Cr-yeast) on growth performance, some blood parameters and neutrophils superoxide anion production, in weaning-stressed piglets. Thirteen crossbred (Landrace × Large White) litters were assigned to Cr-supplemented prestarter diet for 21 d (from 10 d after birth to 7 d post-weaning). Thirteen other litters, forming the control group, were not given supplemental Cr. Blood samples were taken on day 3 post-weaning and 1 h after litters were moved to the post-weaning facilities (day 7 post-weaning). To enhance stress response, ACTH (5 µ g kg−1 BW) was given to some animals immediately before moving. Cromium supplementation did not improve piglet weight or superoxide production by neutrophils. The plasma concentration of non-esterified fatty acids was higher (P < 0.05) and glucose concentration was lower (P < 0.05) at 7 d post-weaning compared with 3 d in both treated and control piglets. In ACTH-challenged piglets, a further lowering of blood glucose was associated with Cr supplementation (P < 0.05), but cortisol and insulin levels were not affected by dietary treatment. These data suggest that Cr supplementation does not reduce weaning stress in piglets. However, in high-stress conditions (as simulated by ACTH challenge) Cr supplementation may improve peripheral glucose utilisation. Key words: Chromium supplement, piglet, blood parameters, weaning stress