The ORNL chopper has been used to measure the neutron total cross sections of samples of fission product samarium and iodine in the thermal and resonance energy regions. At 2200 meters/sec, the total cross section of Sm151 was found to be (15000 ± 1800) barns, and the absorption cross section of I129 (28.0 ± 2) barns. The variation of cross section of Sm151 with energy in the thermal region was found to be strongly affected by a bound level, but in the case of I129 the absorption cross section could be described by a “1/V” dependence. In the higher energy region, resonance parameters were obtained for Sm151, I127, and I129 by area analysis of the observed transmission dips. In addition, a shape analysis method was used for the lower energy resonances in Sm151. The following values for the level spacings and strength functions (per spin state), and resonance absorption integrals were obtained: