Uropathogenic Escherichia coli (UPEC) is the major cause of urinary tract infections worldwide. Outer membrane protease T (OmpT) , as a putative uropathogenic virulence factor , is found more frequently in UPEC than in fecal isolates. This review covers the current progress on substrate specificity of OmpT, resistance to cationic antimicrobial peptides, roles in the fibrinolytic system and bacterial adhesion and invasion.