Screening of 38,000 infants, age 1 to 2 1/2 years, showed a prevalence of 1.3% of strabismus and 0.5% of strabismic amblyopia. Esotropia was more than three times as frequent as exotropia. Approximately half of the cases with esotropia were amblyopic. Eighty-one percent of the cases with exotropia were intermittent, and in 29% the V-pattern was found. Significant ametropia was found in over 50% of the cases with strabismus. Although hypermetropia was the most frequent refraction in children with esotropia, myopia was a frequent finding in both esotropia and exotropia. Anisometroia was particularly frequent in constant unilateral esotropia. Accommodative strabismus was found in 7% of cases with infantile esotropia. In cases with paralytic strabismus, the most frequent muscle involved was the lateral rectus. Significant organic pathology, other than strabismus or amblyopia, was revealed in 0.2% of the series. "Rapid retinoscopy" through undilated pupils is an efficient method in detecting high refractive errors and candidates for nonstrabismic amblyopia in childhood. Since this method of examination is easy to perform, its adoption as a part of screening projects in childhood is recommended. "Rapid retinoscopy" performed by a trained orthoptist is also a useful method for detecting opacities in the ocular media.