The aim of this study was to investigate the developmental process of gastric myoelectrical activity (GMA) in preterm infants. Nineteen healthy preterm infants were studied. GMA was recorded using surface electrogastrography, and six follow-up studies were performed in each subject. Spectral analysis methods were applied to compute the parameters of the electrogastrogram (EGG). The results showed that there was a developmental process of GMA with age during the first 6 mo of life. 1) The percentage of normal slow waves showed a progressive increase after birth (36.7 ± 6.1, 37.8 ± 6.2, 47.0 ± 10.0, 52.2 ± 12.2, 55.2 ± 9.7, and 65.8 ± 13.5% at 1 and 2 wk and 1, 2, 4, and 6 mo, respectively); 2) there was a significant postprandial increase in the percentage of normal slow waves during the first 2 mo after birth; and 3) the percentages of normal slow waves for different gestation ages were not statistically significant. In conclusion, the percentage of normal slow waves is low at birth and there is a developmental process that may be stimulated by enteral feeding.