The 70 children with failure to thrive (FTT) admitted to our hospital over the last five years were reviewed. After extensive evaluations, only 16% received a diagnosis of an organic disorder. In the nonorganic group, 45% of FTT was secondary to improper feeding and 52% was secondary to environmental deprivation. Thirty percent of the children were discharged without a diagnosis. Although there were some important differences between the groups, extensive laboratory data were of little value. Follow-up information revealed that while the children with FTT secondary to poor feeding technics uniformly did well, the outlook for the environmentally deprived group and unknown cause group was frequently poor.