To evaluate possible risk factors for developing recurrent acute otitis media (rAOM), 113 children were followed prospectively from birth to the age of 3 years. One of the aims was to determine whether such risk factors could be identified before the onset of the recurrences, so that optimal care and prophylactic measures could be made available at an early stage in such cases, on the basis of continuous follow-up by an ENT specialist. During the follow-up, 13 children developed rAOM, defined as six or more episodes of acute otitis media (AOM) during a 12-month period, 57 children had occasional episodes of AOM, and 43 children had no AOM at all. Of the children with onset of AOM before 6 months of age, 80% developed frequent episodes of AOM. The frequency of other respiratory tract infections and of family histories of otitis-proneness was higher among rAOM children than among the other children. The development of rAOM was unrelated to such factors as sex, familial history of allergy, duration of breast-feeding, or domestic environment. Nor could attendance at day-care centres be concluded as constituting a risk factor for the development of rAOM. An onset of AOM before 6 months of age was highly predictive of subsequent recurrent bouts of AOM, which emphasizes the importance of correct diagnosis in infants.