The neutron total cross section of 204Pb was studied for neutron energies from 5 to 80 keV, using fast time-of-flight techniques. At least 10 s-wave resonances were observed in this interval in addition to a number of probable p-wave resonances. The average observed s-wave level spacing is 2.7+/-0.5 keV, and the s-wave strength function is (0.55+/-0.2)×10-4. The total cross section of 208Pb was measured from 26 to 84 keV. Resonances were observed at about 70 and 77 keV, both apparently due to l=1 neutrons. The effective nuclear radius R' for 208Pb+n was found to be 8.4+/-0.3 F.