INTRODUCTION:We have reported previously on anin vitromodel to examine tumor cell adherence to metal and plastic laparoscopic ports and to port sites through which they had been passed. This demonstrated that increased numbers of tumor cells were found both on metal ports compared with plastic ports and on the port sites through which metal ports had passed. In this study, thein vivoadherence of such cells to ports and port sites was investigated.METHODS:LIM 1215 tumor cells were injected under direct vision into the pelvises of 16 30‐kg female pigs (range, 15‐70 × 106 cells). A total of 12 ports were inserted through each anterior abdominal wall (6 metal and 6 plastic), and these were either leftin situfor 30 minutes (nondisplaced) or were removed twice and replaced through the original wound (displaced).RESULTS:Increasing the tumor cell inoculum resulted in increased deposition of tumor cells on both ports (P= 0.002) and on the port sites (P= 0.017). Significantly more tumor cells adhered to metal ports than to plastic ports (P= 0.04), although this failed to reach significance for the sites through which metal ports had been passed (P= 0.066). Although displacement of ports did not increase the number of tumor cells that adhered to ports (P= 0.45), this did result in more tumor cells being deposited on the port sites (P= 0.01).CONCLUSIONS:These data suggest that minimizing the number of tumor cells within the abdominal cavity, using plastic ports, and securing ports to prevent inadvertent displacement would be expected to reduce the number of tumor cells deposited in port sites during operative laparoscopy. This may be beneficial in reducing the incidence of port‐site metastases after laparoscopic surgery for gastrointestinal malignancies.