Worm infestations in children caused by roundworms (Ascaris lumbricoides), whipworms (Trichuris trichiura) and hookworms (Ancylostoma duodenale and Necator americanus) are common, largely asymptomatic and responsible for considerable morbidity and occasional mortalities. The majority of South African children remain untreated for these and other helminthic infections. Untreated infections result in adverse effects on growth, nutrition, micronutrient deficiencies, anaemia and a number of cognitive developmental areas. Treatment of more of these infections would significantly improve many aspects of child health. The interaction of worm infections with HIV/AIDS is also of interest. More comprehensive deworming programs, as employed in many other countries, have the potential to provide important improvements to the health of our children at remarkably low cost.