The present report concerns a random sample of 2512 children monitored for acute otitis media up to the age of two years. The criteria given by previous surveys classified from 1.8 to 41.2% of the population as 'otitis-prone', at a mean age varying between 13.4 and 18.8 months. A criterion of at least 4 episodes of acute otitis media during the next 9 months with a 30-day borderline between two distinct episodes yielded 273 children (10.8% of the population) with an acceptable mean age of 15 months. Early onset of acute otitis media was only a weak predictor of susceptibility in either the individual child or the whole population, the sensitivity levels and predictive values being too low for accurate prediction.