A major trend in ulcer management currently is the role of nitric oxide (NO) and its agonists such as L-Arginine in ameliorating gastric ulcers. The current study focuses on the possible effects of L-Arginine supplementation on indomethacin-induced gastric ulcerations in rats. Male Wistar albino rats weighing between 150-180g were used and divided thus: Group I (Control) – saline, 8ml/kg, Group II- L-Arginine 1g/kg B.W for 3 days, Group III- L-Arginine 1g/kg B.W for 7 days. The effect of L-arginine supplementation was on indomethacin-induced gastric ulcerations, ulcer dimensions and histological profile of the gastric mucosa was examined. The result showed that arginine supplementation possesses capabilities of reducing ulcer formation as evident by the lower ulcer scores of the supplemented groups when compared with the Control. The 3-day supplemented group had a significantly lower ulcer score (p<0.05). Ulcer area and width were significantly reduced in the 3-day supplemented group (p<0.05) while the ulcer depth was significantly reduced in both supplemented groups (p<0.01). Histological examination of the gastric tissues showed that the 3-day supplemented group had greater reduction in the level of gastric disturbance than both Control group and the 7-day supplemented group. We proposed that a rapid angiogenetic activity in response to arginine supplementation which then wanes over time may be responsible for this pattern. This study provides evidence that arginine supplementation is beneficial in reducing the risk of gastric ulcer induced by NSAIDS and this is possibly mediated by direct enhancement of angiogenetic activity around the disturbed gastrum.