The effect of low-frequency pulsed electromagnetic field (PEMF) on crude oil rheology was studied on 11 samples of domestic crude oil with a high pour point. Experiments were carried out by using homogeneous single unipolar 70 mu s-wide quasi-square pulses with peak intensities of 1 mT and 5 mT and frequency varying from 8 to 60 Hz. The rheotests were performed at 20, 25, 30, and 35 degrees C, using shear rates in the interval from 16.2 to 438 s(-1). PEMF influenced the rheological behavior of samples by increasing/decreasing the shear stress, but not changing the shape of the flow curves. The PEMF frequency exhibited crucial effects on shear stress, and a certain periodicity in the relation between these two quantities,similar for both PEMF intensities, was observed for all the samples.