PIP: An association between fertility, sibship size, and mid-parental height was analyzed in an endemic rural population of Lahore, Punjab, Pakistan. The study was carried out on the population of Muridke, a town 27 km north of Lahore. Families were visited to record the heights of father and mother, total number of siblings born in each family, and sex of children. The data were analyzed for fertility and mean sibship size in relation to: maternal height (the data are based on 827 siblings consisting of 3337 total siblings born out of which 2870 were alive); paternal height (the data consist of a sample of 860 siblings containing 3420 total siblings out of which 3000 were alive); and mid-parental height (the data are comprised of 790 siblings composed of 3122 total siblings born of which 2693 were alive). The data were analyzed in 3 ways, i.e., fertility and mean sibship size in relation to maternal height, paternal height, and mid-parental height. The maternal heights were arranged into 6 classes. Mean maternal height in the sample if 152.59 +or- 4.48 cm, that of father 164.94 +or- 4.59 cm, and for mid-parental heights the mean is 159.65 +or- 6.00 cm. The highest mean number of total siblings born was not associated with the mean value class, 152-153, rather it was observed in the next higher class, 154-155. The lowest coefficient of variation was seen in the mean value class, though not the variance. If the average range classes, 3 + 4, are combined, this shows higher mean number of total siblings born than the remaining classes, and also the coefficient of variation is the lowest. For paternal heights, the mean value class, 164-165 shows less mean number of children than the next higher class, 166-167. When the average range classes, 4 + 5, are combined together, a higher mean number of total siblings is observed compared with the remaining classes. For mid-parental heights, in the mean value class, 158-159, mean number of total siblings born are more than the other classes. The analysis of the combined average range classes (3 + 4) shows higher mean sibship size compared with the remaining classes.