to determine frequencies of refractive errors in Zairian blacks and to investigate the influence of race upon refraction.we examined the records of all patients seen at the department of Ophthalmology from 1963 to 1972. Refraction was measured by objective (skiascopy) or subjective methods.we found 4326 patients with ametropia, about 16% of the total. The records of 2594 Zairian patients with refractive errors were compared to those of 1417 non Zairian black patients and 315 Caucasian patients. The frequency of spherical refractive errors in Zairian black patients was 56%: (simple myopia: 33% myopia over 5 D: 1%, hypermetropia: 22%), astigmatism was seen in 44% (myopic astigmatism: 31% and hypermetropic astigmatism: 11%). The data of Zairian were similar to those of non-Zairian black patients. Spherical refractive errors in Caucasian patients were found in 46% of the patients (simple myopia: 19%, myopia over 5 D: 2%, hypermetropia: 25%). Astigmatismatic errors were seen in 54% (myopic astigmatism: 27%, hypermetropic astigmatism: 24%, mixed astigmatism: 3%). Hypermetropia increased with age in all groups, but slightly earlier in Zairian patients.Although the data of refractive errors did not show significant differences between Zairian and Caucasian patients, hypermetropic astigmatism seems to be less frequent and myopia more frequent among Zairian patients.