Carbon nanotubes (CNT) are hexagonal arrangements of repetitive carbon atoms, of tubular form, that could be used for different medical applications. In vitro studies have reported their capacity to induce oxidative stress and to stimulate cytokine production. However, in vivo studies focused on their capacity to induce oxidative stress are still limited and controversial. Our aim was to evaluate the capacity of carbon nanotubes solutions with different concentrations to generate oxidative stress in vivo. Material and methods: The study was carried out on male Wistar rats (170±10g), i.p. injected with 1.5 ml single walled CNT (SWCNT) solutions of different concentrations (70g/l, 250 g/l, 390 g/l). ss-DNA-SWCNT water solution was obtained through 7 hr sonication. NaCl was added up to the concentration of 0.9%. Controls were similarly i.p injected with 1.5ml serum. In all groups, malondialdehyde (MDA), protein carbonyls (PC), hydrogen donor ability (HD), sulfhydryl groups (SH) were assessed in blood and hepatic tissue homogenates, 3, 6, 24 and respectively 48 hours after the SWCNT administration. Results: We obtained a significant decrease in HD in test group compared to controls at 24 hr interval (22.3(3.8) vs 16.2(4.5), p=0.009) for 70 g/l SWCNT concentration. For the concentration of 250 g/l SWCNT, oxidative stress parameters showed maximal and significant variations 24 hours after i.p administration, with recovery tendency 24 hours later. For 390 g/l, significant variations of oxidative stress parameters occurred in plasma 3 hours after the administration, and in liver 6 hours after the SWCNT administration. The oxidative stress biomarkers and the antioxidant capacity remained altered 48 hours after SWCNT administration Conclusion: Our results support the ability of ssDNA-SWCNT to generate oxidative stress both in plasma and liver after i.p. administration, the pattern of alterations depending on the concentration of SWCNT solutions.