In the publication, the recent adaption of the modelling program REMO is considered. It was developed by the Environment Modelling Centre (EMC) of the Riga Technical University. The program is compared with the licensed system GROUNDWATER VISTAS. The REMO program is handy for calibration of hydrogeological models. The program was originated in 1990 when the regional hydrogeological model (REMO) for the central part of Latvia have to be created. REMO modelled hydrogeological processes. It was based on the more universal software OMEN (also developed by EMC). To account for hydrogeological processes, some specific modules were included. Since 1996, many hydrogeological models have been developed for Latvia and abroad by using REMO. The models considered problems of well fields supplying drinking water and migration of contaminants in groundwater. During its exploitation, REMO was updated and many special applications were introduced: interpolation of well rates on the model grid, computing of groundwater balance for polygon areas, modelling elements of drainage systems. Because REMO was originated in 1991, the DOS environment and FORTRAN 77 were applied to create REMO. In order to apply resources of modern software and hardware, partial updating and adaptation of REMO has been accomplished: the FORTRAN 90 has been applied in the WINDOWS XP environment; the former maximal grid plane size of 100×100 nodes has been enlarged to 989×989. However, the graphical interface of software module has not been recovered yet, because about 15 its original programme texts are not found. The number of grid planes emains limited n≤9.