  In spite of recent detections of magnetic fields in a number of beta Cephei
and slowly pulsating B (SPB) stars, their impact on stellar rotation,
pulsations, and element diffusion is not sufficiently studied yet. The reason
for this is the lack of knowledge of rotation periods, the magnetic field
strength distribution and temporal variability, and the field geometry. New
longitudinal field measurements of four beta Cephei and candidate beta Cephei
stars, and two SPB stars were acquired with FORS2 at the VLT. These
measurements allowed us to carry out a search for rotation periods and to
constrain the magnetic field geometry for four stars in our sample.
