The adiabatic electron affinities (AEAs), vertical electron affinities (VEAs), and vertical detachment energies (VDEs) of cyclic perfluoroalkanes, c-CnF2n (n = 3-7), and their monotrifluoromethyl derivatives were computed using various pure and hybrid density functionals with DZP++ (polarization and diffuse function augmented double-zeta) basis sets. The theoretical AEA of c-C4F8 at KMLYP/DZP++ is 0.70 eV, which exhibits satisfactory agreement with the 0.63 +/-0.05 eV experimental value. The nonzero-point-corrected AEA of c-C4F8 is predicted to be 0.41 eV at the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ level of theory, which shows a slight deviation of 0.11 eV from the KMLYP estimated value of 0.52 eV for the same. With the zero-point correction from the MP2/6-31 1 G(d) [Gallup, G. A. Chem. Phys. Lett. 2004, 399, 206] level of theory combined with the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ result, the most reliable estimate of AEA Of c-C4F8 is 0.60 eV. c-C3F6(-), c-C4F8(-), and c-C5F10(-) are unusual in preferring planar to near planar ring structures. The ZPE-corrected AEAs of c-CnF2n increase from n = 3 (0.24 eV) to n = 5 (0.77 eV), but then dramatically fall off to 0.40 eV for both n = 6 and n = 7. All of the other functionals predict the same trend. This is due to a change in the structural preference: CsC-C6F12(-) and C-1 C-C7F14(-) are predicted to favor nonplanar rings, each with an exceptionally long C-F bond. (There also is a second, higher energy D-3d minimum for C6F12(-).) The SOMOs as well as the spin density plots of the c-PFA radical anions reveal that the "extra" electron is largely localized on the unique F atoms in the larger n = 6 and n = 7 rings but is delocalized in the multiatom SOMOs of the three- to five-membered ring radical anions. The computed AEAs are much larger than the corresponding VEAs; the latter are not consistent with different functionals. The AEAs are substantially larger when a c-CnF2n fluorine is replaced by a -CF3 group. This behavior is general; PFAs with tertiary C-F bonds have large AEAs. The VDEs for all the anions are substantial, ranging from 1.89 to 3.64 eV at the KMLYP/DZP++ level.