This study was performed to determine the effects of copper proteinate on performance, blood chemistry, lipid peroxidation status, and organs as well as copper deposition in the liver and eggs of laying hens. Seventy-two 30-week-old Bovans laying hens were distributed into four groups with three replicates. Animals were fed basal diet containing at least 17% crude protein and 2,800 kcal/kg metabolizable energy supplemented with either 0, 150, 300, or 450 mg/kg copper as copper proteinate. Supplementation of 150 and 300 mg/kg copper increased egg production, whereas 450 mg/kg copper decreased (p<0.001). Liver copper levels were elevated in 300 and 450 mg/kg copper-supplemented groups (p<0.001). Egg copper contents increased in all treatment groups (p<0.01). An increase in glucose (p<0.001) and decreases in albumin (p<0.01) and total cholesterol (p<0.05) levels were determined with 300 and 450 mg/kg copper. Supplementation of 450 mg/kg copper increased alkaline phosphatase and gamma glutamyl transpeptidase activities (p<0.05), malondialdehyde, and high-density lipoprotein levels (p<0.01) but decreased alanine aminotransferase and lactate dehydrogenase activities (p<0.01). No gross and microscopic changes were observed in the liver and kidneys. These results indicated that 150 and 300 mg/kg copper increased egg production without having marked adverse effects, but 450 mg/kg copper altered some blood chemistry variables and reduced egg production in laying hens.