We present seismic tomography models of the Baikal Rift Zone (BRZ), obtained from regional seismological data recorded in the period 1994-2016. 3D models of P- and S-wave velocity distributions under the BRZ were built down to a depth of 60 km with the LOTOS local seismic tomography algorithm. An overall picture of the heterogeneities coincides with the already existing ideas on the seismic structure of the region: a high-velocity anomaly in the north corresponds to the Siberian Craton; low-velocity anomalies in the western part of the study area are apparently due to the presence of the Cenozoic plume; the Baikal Rift Zone is characterized by a low-velocity anomaly down to a depth of 35-50 km, which accords with the present-day concepts of the Moho discontinuity depth. Moreover, below the BRZ there is a jump in the lower boundary of the low-velocity anomaly, which is in line with the Moho jump recognized in the existing investigations. In addition, based on the results obtained, we identified a number of heterogeneities not revealed earlier. For example, high-velocity near-surface anomalies in the Middle Baikal block, which were interpreted as heavy gabbro-metagabbro bodies, displaced as a result of the Cenozoic strike-slip. Based on the results obtained, as well as on the review of the existing geological and geophysical works, the authors argue in favor of a passive model during the formation of the Baikal Rift.