In a nationwide survey of schistosomiasis conducted in Mali from 1984 to 1989, 56265 individuals from 323 villages had their urine examined parasitologically using a filtration technique. From a sample of 242 children in 3 villages, aged 7 to 14 years, urine samples were collected and tested for haematuria using reagent strips. Analysis of the age-specific prevalence rates of Schistosoma haematobium infection showed a strong positive correlation between the prevalence rate in the 7-14 year-old age group, and both the overall prevalence (r = 0.90; P < 0.001) and the prevalences at other ages. An index was derived from this relationship using the equation: overall prevalence = -1.14 + 0.74 (prevalence in 7-14 year-olds). The sensitivity and specificity of reagent strip testing for microhaematuria as compared to urine filtration were 73.3% and 83.2% respectively. We conclude that reagent strip testing of urine samples collected from a sample of individuals aged 7-14 years would be sufficient to estimate the overall prevalence of Schistosoma haematobium infection in a Malian community and suggest that this assessment procedure be used at the peripheral level of primary health care to decide on treatment regimes.