Recently, the FORS\,1 instrument at the VLT allowed us to detect longitudinal magnetic fields in several slowly pulsating B stars (SPB stars) and in a few $\beta$~Cephei stars. Our dataset proved for the first time that these pulsating B-type stars possess weak mean longitudinal magnetic fields of the order of a few hundred Gauss. We present the results of our observing campaigns and discuss the relation between detected magnetic fields and stellar fundamental parameters.