The aim of the current paper was to elaborate an immobilization method of thrombin receptor agonist peptide (TRAP-6) in biodegradable biocompatible poly(d,l)-lactide-co-glycolide (PLGA) microparticles and to demonstrate the effect of the entrapped peptide for tissue repair, namely for a gastric ulcer treatment in rats. TRAP-6 was entrapped in polymer using w/o/w double emulsion-evaporation technique. The morphology of empty and TRAP-6 loaded microparticles was evaluated by light and scanning electron microscopy (SEM). In vitro release kinetics profile of TRAP-6 from microparticles was studied by HPLC. To investigate gastric mucosal protection effect in vivo, TRAP-6-loaded microparticles were administered in a rat stomach after a previous mucosal injury (a gastric ulcer). Microparticles with entrapped TRAP-6 were found to reduce both an inflammation and proliferation phases of wound healing, and thus accelerated tissue repair in rats.