This study was designed to determine the prevalence of healthy Haemophilus influenzae carriers in a random sample of the preschool population in Catalonia. Oropharyngeal swabs were collected and cultured on chocolate agar supplemented with 260 microg/ml of bacitracin. Four hundred two of the 734 (54.8%) children studied were detected as Haemophilus influenzae carriers: 7 (0.9%) carried serotype b, 14 (1.9%) serotype e, 6 (0.8%) serotype f, and 375 (51%) carried nontypable strains. The results show that, although the prevalence of Haemophilus influenzae carriers is similar to figures reported from other countries, the prevalence of Haemophillus influenzae serotype b carriers is lower and corresponds with the low incidence of invasive disease observed in the Catalan community.