Abstract This work gives an extensive critique of studies on methyl bromide and all its isotopic varieties with special stress on their rotational, vibrational, and rovibrational spectra. The rotational constants of more than 40 vibrational states of CH3Br and 20 of CD3Br, as well as of the ground states of all varieties, were critically examined and corrected where needed. An almost complete set of harmonic and anharmonic constants for CH3Br was derived. From the set of rotation-vibration interaction constants, new accurate equilibrium constants Ae and Be have been evaluated for CH379Br, CH381Br, CD379Br, CD381Br, from which the following equilibrium structure is obtained: r e (CH) = 1.0823 A ; r e (CBr) = 1.9340 A ; α(HCH) = 111.157°.