SummaryThere is a great need for rapid and low-cost identification of communities at high risk of intestinal schistosomiasis. We report the development of a questionnaire approach that may do so. In the first phase, 209 schoolchildren from 3 neighbouring villages in a rural area endemic for intestinal schistosomiasis in western Côte d'Ivoire were screened for Schistosoma mansoni and other helminths on 4 consecutive days using Kato-Katz thick smears. Daily infection prevalences of S. mansoni were high (60%᎐71%) and the cumulative infection prevalence was 92.3%. Infections with hookworms and Ascaris lumbricoides were also frequent, with cumulative prevalences of 60.8% and 38.3%, respectively. On day 3, the presence of Entamoeba histolytica/E. dispar and Giardia lamblia was assessed by a faecal concentration procedure. In the second phase, focus group discussions (FGD) were conducted: in each village one FGD with heavily infected children and one FGD with lightly or S. mansoni-uninfected schoolchildren to assess their perception of morbidity. The aim was to establish local terms indicating S. mansoni infections. 'Diarrhoea', 'blood in the stools', 'stomach disorders' and 4 terms in the local Yacouba/Dioula languages were frequently used by infected children. A simple questionnaire was then developed and the headteachers interviewed all schoolchildren individually. 'Blood in stools', gnon and toto were reported significantly more frequently among moderately and heavily S. mansoni-infected children than by those not or only lightly infected. The term gloujeu indicated borderline significance. The best diagnostic performance was found for 'blood in stool' (sensitivity: 47%; specificity: 76%; positive predictive value: 66%; negative predictive value: 60%). All schistosomiasis infections were treated with a single oral dose of praziquantel (40 mg/kg body weight) and the same questionnaire was re-administered 6 weeks post-treatment. Statistically significantly less children reported having had 'blood in stool' and 'gloujeu' after treatment (McNemar's ( 2 -test, P Ͻ 0.01). We conclude that 'blood in stool', 'gnon', 'toto' and 'gloujeu' are the most reliable reported symptoms for rapid and low-cost identification of communities that are at high risk of S. mansoni infections in Côte d'Ivoire.