A comparative study of four absorbable suture materials, namely; poly-N-acetylglucosamine (Chitin), polyglycolic acid (PGA), plain catgut and chromic catgut, in terms of strength, elongation, tensile strength retention and tissue reaction, was undertaken. The straight pull strength of USP 3-0 size Chitin was over 2.6 kg, compared with PGA, which was over 3.4 kg and the catguts, which were over 2.0 kg. Chitin showed the lowest elongation among the four. The tensile strength retention (TSR) of Chitin in muscle was 45 per cent at 14 days and 7 per cent at 25 days, which was similar to that of PGA. The TSR of Chitin was maintained by 35 per cent in gastric juice, 97 per cent in bile and 100 per cent in pancreatic juice after immersion for 30 days. The corresponding values for PGA were 54 per cent, 0 per cent and 0 per cent, respectively, whereas both catguts had dissolved within 30 days. The tissue reaction of Chitin was similar to that of PGA, whereas the catguts caused more intense tissue reaction.