BACKGROUND: Children are acknowledged as the most vulnerable group to urinary schistosomiasis. OBJECTIVE: To determine the age group(s) of school children considered as the major contributor(s) to the spread of the disease. DESIGN: Observational/Prospective (concurrent) studies. SETTING: Barekuma, Aninkroma and Hiawo Besease, riparian communities in the Ashanti Region of Ghana. SUBJECTS: Hundred children each were randomly selected from Barekuma and Hiawo Besease basic schools with population age profiles between 4 and 18 years. They were then categorised into 4-6, 7-9, 10-12, 13-15 and 16-18 years, respectively. However, at Aninkroma, the entire school population of 119 pupils, aged between 4 and 15 years were used. They were similarly grouped into 4-6, 7-9, 10-12 and 13-15 years, respectively. Urine filtration method was used for isolation and enumeration of S. haematobium eggs from the subjects. The subjects were monitored through repetition of the experiment at fortnightly intervals over four weeks. MAIN OUTCOME MEASURES: Corrected relative Index of Potential Contamination (IPC) expressed as percentage after calculating the crude IPC. RESULTS: The age groups with the highest relative IPCs at Barekuma, Aninkroma and Hiawo Besease were 7-9, 10-12 and 13-15 years, registering 35.6%, 53.9% and 57.7%, respectively. The age group 4-6 years consistently had the lowest IPC in all the communities. CONCLUSION: The age groups 7-9,10-12 and 13-15 years were considered to be the major transmitters of the disease in the communities.