The concentrations of 226Ra, 238U and 210Pb have been measured in waters from the Mussel Bed and the Rose Garden thermal fields at the Galapagos spreading center over a temperature range of ~2.5--16 ¿C. The 226Ra-T plots yield slopes of 0.112 and 0.036 dpm/kg ¿C for the Mussel Bed and the Rose Garden respectively yielding a global hydrothermal 226Ra flux less than 5% of that required to sustain the oceanic inventory. 238U concentration in waters <9 ¿C is the same as that in ambient sea water whereas water hotter than ~9 ¿C shows a decreasing trend with temperature to zero 238U at ~29 ¿C. 210Pb concentration in Mussel Bed increases with temperature, and extrapolated to ~350 ¿C yields a 210Pb concentration considerably less than that expected from 222Rn decay and basalt alteration.