Salivary gland tumors account for 3-6% of tumors of the head and neck. About 80% of salivary gland tumors occur in parotid glands. Oxidative stress (OS) is implicated in the origin, development, and whole-body effects of various tumors. There are no data on the occurrence of OS in the parotid gland tumors. The aim of this study was to ascertain if whole-body OS accompanies parotid gland tumors, based first of all on oxidative modifications of blood serum proteins and other markers of OS in the serum of the patients. The group studied included 17 patients with pleomorphic adenoma, 9 patients with Warthin's tumor, 8 patients with acinic cell carcinoma, and 24 age-matched controls. We found increased concentration of interleukin 4 in patients with acinic cell carcinoma, decreased plasma thiols, increased AOPP concentration, and decreased FRAP of blood serum in all groups of the patients while protein oxidative modifications assessed fluorimetrically, protein carbonyls, protein nitration, malondialdehyde concentration, and serum ABTS⁎-scavenging capacity were unchanged. These data indicate the occurrence of OS in patients with parotid gland tumors and point to various sensitivities of OS markers.