Traditional NSAIDs, selective cyclooxygenase (COX)-2 inhibitors, and inhibitors of nitric oxide synthase (NOS) impair the healing of pre-existing gastric ulcers. However, the role of COX-1 (with or without impairment of COX-2) and the interaction between COX and NOS isoforms during healing are less clear. Thus, we investigated healing and regulation of COX and NOS isoforms during ulcer healing in COX-1 and COX-2 deficiency and inhibition mouse models. In this study, female wild-type, COX-1^-/- and COX-2^-/- mice with gastric ulcers induced by cryoprobe were treated intragastrically with vehicle, selective COX-1 (SC-560), COX-2 (celecoxib, rofecoxib, and valdedoxib), and unselective COX (piroxicam) inhibitors. Ulcer healing parameters, messenger RNA (mRNA) expression, and activity of COX and NOS were quantified. Gene disruption or inhibition of COX-1 did not impair ulcer healing. In contrast, COX-2 gene disruption and COX-2 inhibitors moderately impaired wound healing. More severe healing impairment was found in dual (SC-560+rofecoxib) and unselective (piroxicam) COX inhibition and combined COX-impairment (in COX-1^-/- mice with COX-2 inhibition and COX-2^-/- mice with COX-1 inhibition). In the ulcerated repair tissue, COX-2 mRNA in COX-1^-/- mice, COX-1 mRNA in COX-2^-/- mice, and, remarkably, NOS-2 and NOS-3 mRNA in COX-impaired mice were more up-regulated than in wild-type mice. This study demonstrates that COX-2 is a key mediator in gastric wound healing. In contrast, COX-1 has no significant role in healing when COX-2 is unimpaired, but becomes important when COX-2 is impaired. As counter-regulatory mechanisms, mRNA of COX and NOS isoforms were increased during healing in COX-impaired mice.