Declines in hydraulic head and accompanying land subsidence in the Nobi Plain have been severe due to pumping of groundwater for industrial and agricultural uses during the last 35 years. For monitoring these phenomena, more than 50 observation sites with one to three nested wells, with depths ranging from 50 to 400 m below the land surface, were installed. Vertical temperature profiles and hydraulic heads at 41 sites were measured to evaluate the effect of groundwater flow on the subsurface thermal regime. Results of observations and numerical analysis of transient groundwater flow and heat transfer that includes the effects of pumping suggest that the subsurface temperature distribution is affected by the natural regional groundwater flow but hardly at all by pumping within the last 35 years. However, a detailed analysis of pumping effects suggests that subsurface temperature decreases slightly at depths shallower than -100 m because of induced recharge by the heavy pumping around the center of the plain. When municipality controlled the pumping amount due to increasing subsidence in 1973, the ratio of temperature decrease was changed. Moreover, the simulation model shows that the subsurface temperature will be significantly affected by pumping after 100 years from the beginning of pumping.