The emergence of both absorbable and nonabsorbable synthetic materials has been primary among the many new developments in suture materials. This is a study of 16 types of natural and synthetic suture materials and their resistance to both gram-positive and gram-negative infections. Four hundred and twenty suture inplants were made in the Edlich mouse model. The 16 different sutures were compared to appropriate controls and graded by the degree of infectibility. Synthetic sutures were superior in all areas. The monofilament sutures performed better than the multifilament sutures. Lubricating coatings had no effect on infectibility. Natural sutures performed poorly and should not be used in wounds that are potentially susceptible to infection.