Summary. Growth monitoring is so far not implemented on a large scale in the Somali health services. Available reports indicate that growth faltering is common. However, the use of growth charts as a tool for health education has been questioned. This study examines the ability of 199, predominantly illiterate, rural Somali mothers to understand the growth chart message after an intensive period of growth chart use and education. During a home-based interview the mothers were asked to combine a set of four growth curves with a set of four pictures, showing the corresponding developments of four children. The mothers managed significantly better to interpret the charts than could be expected by chance alone. Maternal age, number of children and literacy did not differ much between those who correctly and incorrectly combined pictures and charts. Almost all mothers recognised the value of the growth chart as being good for the control and promotion of their children's health and/or growth. We conclude that the growth chart may be an applicable and appropriate tool even with illiterate mothers, provided that other prerequisites for successful growth monitoring, e.g. appropriate health services, are available.