The relationship between diarrheal diseases and growth increments in total body length and weight was investigated in 716 rural Ladino Guatemalan children. Data on diarrheal diseases were provided by the mothers through retrospective surveys carried out at 14‐day intervals. Increments in length and weight, semestral from near birth to four years and yearly thence to seven, were related to days ill with diarrheal diseases during the same time interval. Because the data here reported were collected over a two year period, a child may have had information for more than one period. In total, 1,343 child periods were investigated. Days ill with diarrheal diseases were found to be significantly associated with reduced growth in length and weight. It was assumed that the average differences in growth by seven years of age between children in the present sample and children from well‐to‐do societies, are mainly a function of environmental differences and consequently, a measure of the extent of growth retardation. By expressing the growth retardation specifically associated with diarrheal diseases as a fraction of the above differences it was then estimated that around 10% of this growth retardation was associated with diarrheal diseases. Copyright © 1975 Wiley‐Liss, Inc., A Wiley Company