In this study, we investigated the effect of 6 weeks of swimming training on the ecto-nucleotidase activities and platelet aggregation from rats that developed hypertension in response to oral administration of L: -NAME. The rats were divided into four groups: control (n = 10), exercise (n = 10), L: -NAME (n = 10), and exercise L: -NAME (n = 10). The animals were trained five times per week in an adapted swimming system for 60 min with a gradual increase of the workload up to 5 % of animal's body weight. The results showed an increase in ATP, ADP, AMP, and adenosine hydrolysis, indicating an augment in NTPDase (from 35.3 ± 8.1 to 53.0 ± 15.1 nmol Pi/min/mg protein for ATP; and from 21.7 ± 7.0 to 46.4 ± 15.6 nmol Pi/min/mg protein for ADP as substrate), ecto-5'-nucleotidase (from 8.0 ± 5.7 to 28.1 ± 6.9 nmol Pi/min/mg protein), and ADA (from 0.8 ± 0.5 to 3.9 ± 0.8 U/L) activities in platelets from L: -NAME-treated rats when compared to other groups (p < 0.05). A significant augment on platelet aggregation in L: -NAME group was also observed. Exercise training was efficient in preventing these alterations in the exercise L: -NAME group, besides showing a significant hypotensive effect. In conclusion, our results clearly indicated a protector action of moderate intensity exercise on nucleotides and nucleoside hydrolysis and on platelet aggregation, which highlights the exercise training effect to avoid hypertension complications related to ecto-nucleotidase activities.