The lactational changes in content and distribution of gangliosides in human milk from Spanish and Panamanian mothers delivering term newborns were studied. There were no statistically significant differences in the concentration of gangliosides between Spanish and Panamanian milk. The ganglioside content expressed as a function of total milk lipids tended to decrease as lactation progressed in both types of milk. There was a significant correlation (r=0.5896; p=0.0062) between ganglioside and total lipid contents in Panamanian milk. However, in Spanish milk, the correlation was not significant (r=0.1516; p=0.3439). We did not detect important differences in the relative concentrations of individual gangliosides during lactation among milk samples from Spanish and Panamanian mothers. For both of them, G(D3) was the most abundant ganglioside in colostrum, whilst in mature milk it was G(M3).