The aim of this study was to assess whether α-tocopherol administration prevented alterations in the ectonucleotidase activities and platelet aggregation induced by high-fat diet in rats. Thus, we examined four groups of male rats which received standard diet, high-fat diet (HFD), α-tocopherol (α-Toc), and high-fat diet plus α-tocopherol. HFD was administered ad libitum and α-Toc by gavage using a dose of 50 mg/kg. After 3 months of treatment, animals were submitted to euthanasia, and blood samples were collected for biochemical assays. Results demonstrate that NTPDase, ectonucleotide pyrophosphatase/phosphodiesterase, and 5'-nucleotidase activities were significantly decreased in platelets of HFD group, while that adenosine deaminase (ADA) activity was significantly increased in this group in comparison to the other groups (P < 0.05). When rats that received HFD were treated with α-Toc, the activities of these enzymes were similar to the control, but ADA activity was significantly increased in relation to the control and α-Toc group (P < 0.05). HFD group showed an increased in platelet aggregation in comparison to the other groups, and treatment with α-Toc significantly reduced platelet aggregation in this group. These findings demonstrated that HFD alters platelet aggregation and purinergic signaling in the platelets and that treatment with α-Toc was capable of modulating the adenine nucleotide hydrolysis in this experimental condition.