Summary
During a period of 12 months 1 231 Lebanese Arab children of low socio‐economic class, 3–48 months of age living in three locations were measured. The measurements were weight, height, head circumference and mid‐arm circumference. The results were expressed as percentage of international standards for boys and girls separately. The patterns of deviation from the standard values varied according to the measurement. In general for both sexes there was a falling off between 6 and 18 months, greatest for weight and mid‐arm circumference with some recovery later, and less for height and head circumference without recovery later. The possible influences of location and season of observation and birth were studied. Using these four somatic measurements an Index of Thriving was developed for the subsequent study of contrasting groups of “control” and “failure to thrive” children. The use of this and other simple means of assessing failure to thrive in the field is discussed.