We present a 23-year-old female with Glycogen storage disease Ib (GSD Ib) who was diagnosed with ulcerative colitis-like inflammatory bowel disease (IBD) at 7 years of age. G-CSF therapy reversed the IBD, was required to maintain IBD remission and was well tolerated. Neutrophil functions at time of diagnosis showed impaired chemotaxis but normal superoxide anion production and bactericidal activity. Ulcerative colitis-like IBD may also be seen in GSD Ib and is responsive to G-CSF therapy. Neutrophil dysfunction is variable among patients with GSD Ib.