The NMR spectrum of the nonmagnetic lanthanum ion in charge-ordered La0.5Ca0.5MnO3 and La0.33Ca0.67MnO3 is studied theoretically. It is shown that the dominant role in the formation of the spectrum is played by the anisotropic hyperfine interaction involving polarization of the outer electronic p shells of lanthanum. The model proposed permits an adequate description of experimental data.