Detection and monitoring childhood growth disorders requires the correct use of growth charts. A check on the accuracy of every point plotted on Gairdner-Pearson growth charts of premature infants in a hospital paediatric department was carried out. Errors beyond set limits were recorded. Of 611 points plotted on the growth charts of 50 premature infants who were at least 1 year of age at the time of the study, there were 173 (28.5%) points plotted in error. Altogether 94.7% of the errors occurred when plotting the age along the horizontal (X) axis of the growth chart, irrespective of whether weight, length, or head circumference was being measured. There was no evidence that the errors caused appreciable changes in clinical management. Potential sources of error identified were failure to adjust for prematurity correctly, inaccuracy in calculating age, and the use of the logarithmic scale. These errors could be serious and it is important that there should be greater vigilance in using growth charts. The use of age calculators or improved chart design is recommended. Assessment of the use of other growth charts in different settings is also suggested.