Prediction of the room-temperature fatigue life of Type-347 stainless steel, irradiated to 5.5 × 1021 and 11 × 1021 n/cm2, was attempted from tensile tests and the use of Manson's relationship. It was found that the total strain vs cycles-to-failure for irradiated Type-347 stainless steel can be predicted reasonably well for total strains of 1 to 2% at both levels of irradiation. However, the predicted fatigue lives were conservative for total strains that are <1% for material irradiated to a fast fluence of 11 × 1021 n/cm2. Not enough experimental data points were available to correlate the measured fatigue life with predicted fatigue life at total strains of <1% for stainless steel irradiated to a fast fluence of 5.5 × 1021 n/cm2.