Abstract: The effect of copper and zinc supplementation on serum haptoglobin and milk production performance was tested in a 20 weeks feeding trial with 40 Holstein-Friesian lactating cows, devided in 2 equal groups (supplemented and control). At 10-20 days post calving cows began receiving either a diet containing supplemental Cu and Zn sulphate (19.1±0.8 ppm Cu and 61.7±6.8 ppm Zn) or a diet without mineral supplement (3.1±0.4 ppm Cu, 9.2±1.1 ppm Zn). Milk and blood samples were collected six times every 28 days. Ten subjects of each group were randomly assigned to skin biopsies of the periorbital area at the end and the beginning of the study. Feeding inorganic Cu and Zn increased (p<0.001) plasma Cu and Zn values and significant interactions (p<0.001) was found between time and supplementation on plasma Cu and Zn levels. Serum haptoglobin values were lower (p = 0.24) in cows from supplemented group (0.096±0.006 g L^-1) relative to the control group (0.099±0.009 g L^-1). There was no effect of time (p = 0.21) and no significant interaction (p = 0.35) between time and supplementation on serum haptoglobin levels. The Body Condition Score (BCS) was higher in supplemented group than in those that did not receive supplemental minerals (2.82 vs. 2.75, p = 0.03) but no significant interaction was found between time and supplementation on BCS (p = 0.85). Feeding inorganic Cu and Zn reduced periorbital hypopigmentation in cows. Supplementing Cu and Zn comparing to the control cows had higher yield of milk (23 vs. 22 kg day^-1, p = 0.004), milk crude protein (3.3 vs. 3.2%, p = 0.14), milk fat (4.16 vs. 4.09%, p = 0.002), milk lactose (4.82 vs. 4.79 g kg^-1, p = 0.32) and milk energy (0.74 vs. 0.75 Mcal kg^-1, p = 0.27) however, the response to supplementation tended to be inconsistent over time for production indicators as indicated by time x supplementation interactions (p>0.15). Supplemented group had lower SCC compared to the control cows (246,000 vs. 288,000 cells mL^-1, p = 0.02) but no significant interaction was found between time and supplementation on SCC (p = 0.47). Supplementing with 1.5 g CuSO₄A5H₂O and 5 g ZnSO₄A7H₂O/cow/week for 1st 20 weeks of lactation can significant improve health and milk production performances in a deficient area.