Burst abdomen, incisional hernia and sinus formation continue to bedevil the surgeon. Significant associated factors include postoperative wound infection and the suture material used. A series of experiments was therefore designed to test suture materials for their use in infected abdominal would closure. The nearest to the ideal, is a monofilament nonabsorbable suture (monofilament nylon). It has a low infectivity, resulted in satisfactory would tissue strength when used in infected wounds, and retained its strength. Infected, braided sutures of silk, nylon and polyglycolic acid even after 70 days were seen to contain bacteria and polymorphonuclear cells when examined electron microscopically. Absorption of silk and polyglycolic acid and encapsulation of non-absorbable braided nylon was delayed by the presence of infection. Monofilament nylon, in contrast, was unaffected, a fibrous capsule having formed by 10 days even in the infected state.