Meconium disease (MD) results in intestinal obstruction in the neonate where tenacious meconium is found in the distal ileum and proximal colon. The obstructive symptoms improve at several days of age after some of the meconium is passed. We observed premature infants with MD who underwent ileostomy for intestinal obstruction due to tenacious meconium. Afterward, meconium was passed well and the clinical symptoms improved. After closing the ileostomy, growth and defecation became normal. The MD in our cases was documented by histologic changes in the maturation of ganglion cells observed at the time of ileostomy creation and closure. For an objective evaluation of the maturation of intestinal ganglion cells (IGC), we attempted to distinguish immature from mature cells by the expression of cathepsin D. We examined the distribution of cathepsin D in IGC in patients with MD to test the hypothesis that ganglion-cell immaturity might be related to MD. In ganglion cells at the time of ileostomy, cathepsin D was detected in the perinuclear cytoplasm (immature staining pattern), while at the time of ileostomy closure it was detected in intense granules throughout the cytoplasm (mature staining pattern). We propose that it would be possible to evaluate the maturation of IGC by the intracellular distribution of cathepsin D in MD and suggest that immaturity of IGC might be the cause of MD.