An investigation was conducted on creep behaviors of polypropylene sutures under different temperatures and stress levels in a temperature-controlled water bath. The study showed that temperature and stress level significantly affected the creep behaviors of the sutures. High temperature and stress level resulted in large creep and permanent deformation to the sutures. The creep data could be well described by an empirical formula. For most of the test conditions, the creep tests caused limited permanent deformation in sutures. Dependency of the permanent deformation on temperature may be illustrated by an Arrhenius-type equation. The tensile properties of the sutures were not adversely affected by a short-term creep test, indicating good mechanical performance for the polypropylene sutures. For the creep experiment of less than 3 h, the creep rupture of the sutures was observed at a stress level of 220 MPa and temperatures greater than or equal to37degreesC. (C) 2003 Wiley Periodicals, Inc.