Geophysical prospecting of the so-called Zelenka tumulus, carried out in 1984-1985 with the aim of determining whether archaeological excavations were to be undertaken is described. The tumulus is located near the village of Bulgarevo in northeast Bulgaria. The prospecting involved the use of a complex of geophysical methods including: electrical profiling according to a circular and radial system of observation; proton magnetometry and gradientometry according to a rectangular system of observation; and metal detectors. The results were processed using the ARGUS geophysical system on an IBM 370/145 computer. Zones with anomalous values of the parameters studied, as well as with regular and well-manifested linear or oval configuration, were localized. Conclusions are reached about the character and the form of the possible disturbance, and recommendations are given for the archaeological prospecting of the Zelenka tumulus.