Long- and short-term reactions of reproductive tract tissue to microsurgical suture materials were compared. The five materials were: polyglactin 910 (Vicryl), polyglycolic acid (Dexon-S), polypropylene (Prolene), nylon (Ethilon and Dermalon) and chromic catgut; the calibers ranged from 6-0 to 10-0. Sixteen days after suture placement the smallest tissue reaction was seen with 9-0 and 10-0 suture materials; Dexon-S caused a slightly greater reaction than did Vicryl. Prolene, 8-0 and 9-0, produced the smallest tissue response when compared to other sutures of similar size. Larger sutures incited greater tissue reactions. Forty-two days after placement, each suture was associated with similar or lower reaction scores than those observed at 16 days. At 90 days all the Dexon-S sutures had been absorbed. Vicryl had less of a late reaction as compared to the other sutures. Reactions persisted longer with nonabsorbable suture, and the tissue response depended on both the suture material and caliber. Vicryl, 8-0 to 10-0, incited the smallest short- and long-term tissue reaction; at those sizes it seems optimal for reconstructive tubal surgery.