The results of our spectral and spectropolarimetric observations of selected OB and WR stars are reviewed. Regular variations of line profiles with periods ranging from several hours to days were detected in spectra of all the program stars. The revealed variations are caused by rotational modulation, non-radial pulsations, and photospheric small-scale inhomogeneities in the expanding atmospheres. We review the available measurements of the magnetic fields of OB and WR stars and compile a catalog of magnetic OB stars. Based on our data, we confirm that magnetic field strengths are distributed according to a power law with a degree of 2-2.5. It is also concluded that average magnetic fields of O stars are nearly one order weaker than those for the B stars.