Most growth monitoring programmes in developing countries have not been successful in reducing malnutrition. This is due, at least in part, to the exclusion of mothers from the process of growth monitoring. An essential requisite for greater participation is for mothers to understand the meaning of a growth chart. The ‘Growth Monitoring Teaching Aid’ (GMTA) is an educational game which attempts to expedite the process of understanding growth curves by simulating the growth curve of a child using water added to a bucket suspended below the direct recording scales. Thirty mothers were divided into an experimental group who used the GMTA for 2–4 h and a control group who did not use it. Six questions were used to test each subject's understanding of growth curves. Paired t tests revealed that the experimental group significantly increased their understanding of growth, whereas the control group did not. The mean score for the experimental group prior to playing the game was 1.43; this increased to 5.27 after playing the game (P < 0.0001). The GMTA by rapidly improving the present poor level of understanding of growth curves, may allow greater maternal participation in growth monitoring.