[en] The borehole geophysical methods have been utilized on the Loviisa power plant site to resolve hydrogeological conditions. Late in 1983 radiometric, electrical and acoustic logging was performed by BPB Instruments Ltd. The types of sondes employed were neutron-neutron, gamma-gamma, natural background radiation, caliper, sonic and dipmeter. Boreholes Y1, Y4, Y5, Y8 and Y11 were investigated. The results show that these methods can be applied succesfully to evaluate geomechanical parameters in crystalline bedrock environment. Especially the dipmeter and acoustic logging seem to detect efficiently possible hydraulic conductive fractures and their orientation. Radiometric methods have not a resolution high enough to localise small scale features but provides, however, valuable lithological and supplementary information of fracturing. Logs from borehole Y1 are appended to this paper. The survey provided new information of absolute fracture orientations that is important in modelling bedrock conditions in the area and to combine with results of cross-hole geophysical methods. Further processing of the results and development of interpretational models is important to utilize the discussed borehole methods in crystalline rock mass investigations