Surgicel is a hemostatic agent that consists of oxidized regenerated cellulose and used in surgical procedures as an aid to bleeding control. It is left in the operation site for hemostasis, could cause an operation by mimicking the recurrence of tumor, as in our patient. A 3-year-old boy was operated by us at the age of 40 days and 2.5 years, respectively, due to pelvic neuroblastoma. He was re-operated for mimicking recurrence or residue tumor secondary to the prior placement of Surgicel within the peritoneal cavity. Re-laparotomy was performed and the mass approximately 2.8 × 2×1 cm in size in front of the right ureter and iliac vessels and behind the bladder was removed by blunt and sharp dissection without damaging these organs. While gelatinous content was evacuated from this mass, there was no apparent tumor appearance. Pathology report was reported as fibrotic tissue characterized by foreign body and foreign body giant cells. The postoperative period was uneventful and he was discharged on the 2nd postoperative day. In the light of our case, the use of hemostatic agents should be kept to a minimum and should not be left in the body unless it is difficult. Thus, unnecessary examination or recurrent surgery can be avoided.