The nylon clamp is a polyamide 6.6 device that the same material of surgical nylon. It's designed for use in electric-hydraulic engineering with a brake system without return, providing a safe handling. It's sterilized by autoclave without reducing the tensile strength. Currently has been used in vascular ligation in different surgeries. The study aimed to evaluate the tissue reaction produced by transparent and color nylon clamps in guinea pigs (Cavia porcellus). We used fifteen male guinea pigs, aged between five to eight months and an average weight of 627 grams. The implantation was performed on all animals using segments of surgical nylon - (control group), fragments of transparent and color nylon clamps (research groups). Three groups of five animals were formed according to the biopsy time for histopathology exam. In group 1 the biopsy was performed on the seventh day after the implantation, group 2 on the fifteenth day and group 3 on the ninetieth day after the implantation. On the seventh day, the tissue reaction was moderate and mixed for the three materials with a fibroblast proliferation, vascularization, granulation tissue and presence of giant cells. On the fifteenth day the tissue reaction was similar to that observed on the seventh day but with presence of giant cells only in nylon suture samples. On the ninetieth day was observed a mild inflammatory reaction. The tissue reactions observed between transparent and color nylon clamps and surgical nylon were similar during the study period and no significant statistical difference was observed.