Cl-35 quadrupole coupling constants (C-Q), asymmetry parameters (eta(Q)), and isotropic chemical shifts (delta(iso)) have been determined for a series of inorganic perchlorates from Cl-35 magic-angle spinning (MAS) NMR spectra at 14.1 T. Illustrative Cl-37 MAS NMR spectra are obtained and analyzed for some of the samples. For perchlorate anions with quadrupolar couplings less than about 1 MHz, the Cl-35/Cl-37 NMR parameters are most precisely determined from the full manifold of spinning sidebands observed fur the satellite transitions while line-shape analysis of the central transition is employed for the somewhat larger quadrupolar couplings. The environments for the individual perchlorate anions are best characterized by the quadrupole coupling parameters (e.g., C-Q ranges from 0.3 to 3.0 MHz), while the dispersion in the isotropic Cl-35 chemical shifts is small (1029 ppm < delta(iso) < 1049 ppm) for the perchlorates studied. Due to the variation in quadrupole coupling parameters, Cl-35 MAS NMR may conveniently be employed for identification of anhydrous and hydrated phases of perchlorates, in studies of phase transitions, hydration reactions, and the composition of mixed phases. The perchlorates studied include anhydrous KClO4, RbClO4, CsClO4, (CH3)(4)NClO4, and the anhydrous and/or hydrated farms of LiClO4, NaClO4, Mg(ClO4)(2), Ba(ClO4)(2), and Cd(ClO4)(2). The Cl-35 MAS NMR spectra of LiClO4, Mg(ClO4)(2), and Ba(ClO4)(2), for which the crystal structures are unknown, reveal that each of these salts possesses a single perchlorate site in the asyInmetric unit. The Cl-35 NMR data for Mg(ClO4)(2) and Ba(ClO4)(2) suggest that these two samples are isostructural. Relationships between the Cl-35 NMR parameters and crystal symmetries are discussed for the other perchlorates: where crystal structure data have been reported.