We study the electric-field effects on the spin polarization (P) in dependence of the strength and orientation of the magnetic field in GaAs quantum wells by photoluminescence measurements. The P in a transverse magnetic field is found to oscillate. The transverse electron and heavy-hole g-factors are estimated from the dependences of the oscillation frequency on magnetic field and applied bias. Measurements with the angular variations in the magnetic field show that both the oscillation frequency and decay rate are increased with increasing the angle from the transverse direction. It is, however, shown that the application of the bias to the quantum wells weakens the exchange interaction between the electron and hole spins. 鲰09 American Institute of Physics