In order to search for X-ray time variability among early-type stars we have investigated ROSAT X-ray data of OB-type stars. Here we present typical examples for ROSAT PSPC X-ray light curves of OB-type stars covering time scales of 24 hours up to 2.5 years. We show that X-ray variability is not common among these stars and discuss our result in the context of the model for the X-ray production by shock-heated gas present in the winds of these stars.