Slettebak has observed that the primary of the visual binary ADS 3910 is a normal B5 V star while the secondary, 0 2 mag fainter, is classified as A0p with abnormally weak lines. The UB V colors correspond to B5 for ADS 3910 A and to B6 for B. The components are separately by 39" and have radial velocities of -3 km/sec for A and -4 km/sec for B. In the absence of good proper motions we conclude that the system is physical. A high-dispersion analysis of both components shows that ADS 3910 A has the composition and atmospheric parameters of a normal B5 V star while ADS 3910 B is a B6 V star with low abundances (relative to H) of all elements measurable The abundance deficiencies range from factors of about 10 for Fe and Si to about 100 for He. It is conjectured that ADS 3910 B has undergone surface activity of some kind and that it is probably related to the peculiar A stars and to the stars.