Silicone rubber PEG tubes or replacements were recovered from 111 patients and examined for blockage, dilatations, tears, breaks, or loss of elasticity. All irregularities were stained and examined for fungus using lactophenol cotton blue stain. The intraabdominal portion of the PEG failed from obstructions, loss of elasticity, or tears related to fungus colonies in 36% of cases. An additional 34% were colonized with fungi but did not fail. On frozen section, the fungus invaded the wall of the tubing. The extraabdominal PEG tubing failed from fungi in 12, and 10 additional tubes had colonizations. Nine tubes had distal clogging with crystalline material that is believed to arise from medication. Fungus tube failure occurred in 37% of the tubes in place 250 days and in 70% of tubes in place 450 days. Fungus is an important cause of PEG failure; recommendations are provided to maintain tube patency.