Two hundred and thirty three patients with major laparotomy wounds, either midline or transverse, were randomly allocated to mass closure using No 1 (BPC) polyamide (Nylon) or polydioxanone suture (PDS). Wounds were assessed during the hospital stay and postoperatively in outpatients, at six weeks and six months, for evidence of wound failure or wound infection. Two wound failures occurred in the PDS group (one burst abdomen and one incisional hernia) although neither was directly attributable to suture failure. The overall wound infection rate was 13.3%; 2.9% being major infections and the majority (two thirds) occurring in the PDS group. There were no reported wound sinuses or wound pain in either group at six months. Polydioxanone suture may be an alternative to polyamide for laparotomy closure but is associated with a higher, though not statistically significant, incidence of wound failure and infection.