Cylindrical proportional counters were used to measure the scalar neutron flux in the core and reflector of the 235U-fueled fast subcritical reactors, STSF-7 and -9. These data have been compared with time-of-flight angular spectrum measurements in the same reactors, and with transport theory calculations of these assemblies utilizing ENDF/B-III cross sections. The agreement of the two measurement techniques at high energy indicates that the emission time correction procedures used for the time-of-flight studies on subcritical (keff = ≈0.92) assemblies with a 220-m flight path are reliable. At intermediate energies, the two types of measurements and the calculations were in good agreement for the STSF-9 oxide-fueled core, but significantly different for the metal-fueled STSF-7 core in the region of fine structure associated with the pronounced aluminum resonances below 300 keV. The time-of-flight data exhibited some energy mismatch here, and the 4π counter was subjected to more aluminum “shielding” than allowed for in the calculations. The shielding effect was strongest in the metal-fueled STSF-7 core, because of the absence of the oxygen moderator. At low energy, where the Doppler effects of the thermal coefficient of reactivity are concentrated, the calculations underpredict the flux. The time-of-flight data, which are the most reliable here, show the greatest disagreement with theory.