Puga and Chumathang Geothermal fields are situated near the collided junction of the Indian and Asian Crystal plates and thermal activity in these fields is attributed to the widespread igneous activity of Upper Cretaceous to late Tertiary age. A deep suture zone, recognised in between these two fields and the associated faults provide channels for the upward migration of the thermal fluids. High concentrations of Cl, F, Si02, B, Na, Li, Rb, Cs in thermal fluids signify contribution of magmatic bodies towards heat, and fluid supply. These fields are characterized by high heat flow conditions (13 HFU), abnormal shallow geothermal gradients (0.7 - 2.5 c/m) , high base temperature (220 - 270 C) as obtained by alkalia and Ne-K-Ca geothermometry and low resistivity values (2-20 ohm.m.). Low resistivity zones occupy on an area of three and one sq.km. and extend down to maximum depths of 300 m. and 130 m. at Puga and Chumathang respectively. Shallow drilling (28-130 m.) has established the existence of wet steam reservoirs under moderate pressure (2-4.5 kg/cm^2). Hot fluid (95-135 C) discharges from eight flowing wells ranged from 7.5 to 30 t/h. These thermal fluids are stored in the partly consolidated fluvioglacial deposits of Quarternary to Recent age. The occurrence of a limestone layer in the country rock at Puga brightens the prospects of getting good reservoir at depth. In both these fields two aquifers have been recognised, each having sizeable potential for retaining ground water. The ground water recharge is mainly through snow melt from glaciers in the case of Puga field and principally from Indus river in the case of Chumathangfield