The U.S. Fusion Engineering Device (FED) was used as a basis to investigate the uncertainties of several neutronics performance parameters that arise due to nuclear data uncertainties. The neutron flux distribution was calculated using the discrete-ordinates transport code ANISN. Nuclear data considered were from the VITAMIN-C (DLC-41) library. Atomic displacement rate in the TF coil copper stabilizer, nuclear heating in the epoxybased insulation material and TF coil, and energy multiplication were estimated. The cross section sensitivity study was performed using the sensitivity analysis code SWANLAKE. It shows that the copper atomic displacement rate in the inboard TF coil is known within ± 24 %. The nuclear heating in the inboard insulation material and TF coil are known within ± 21 % and ± 12.5 %, respectively. The uncertainties are primarily due to the iron inelastic scattering cross sections in the 14 MeV energy range.