Cellulose foreign body was initially described by the authors as a cause of granulomatous peritonitis implicating disposable surgical fabrics. The purpose of this study was to establish the incidence, origin, and clinical significance of the lesion. Of 7,500 surgical specimens and autopsies from surgical mortalities reviewed by one pathologist during a two and a half year study period, forty-five cases of cellulose foreign body granulomas were identified by light microscopy. They were examined with polarization technics and scanning electron microscopy in an attempt to determine the source of the cellulose fibers as either cotton or a wood product. The forty-five cases were identified in patients who had at least one previous surgical procedure involving the same area. Twenty-seven cases were extraperitoneal. Eighteen were located in the peritoneal cavity of which five were found at autopsy and thriteen were identified at laparotomy. Two patients had granulomatous peritonitis and six had mechanical small bowel obstruction associated with the granulomas. During the study period there were sixty operative patients of small bowel obstruction; forty-nine were due to adhesions of which thirty-seven had lysis of adhesions without biopsy. Of the twelve patients with surgical specimens, cellulose granulomas were present in six. This suggests that cellulose foreign body granuloma may be a significant cause of intestinal obstruction. The origin of the cellulose could not be definitively established in most cases because of loss of morphologic characteristics. However, fibers were positively identified as wood in two of ten cases (20 per cent) examined with scanning electron microscopy, which supports the thesis that they were derived from disposable surgical fabrics.