The spectra of all the methylated ureas, ethylene urea, and certain alkyl, alkylaryl, and aryl ureas are reported and discussed. The spectra are all relatively simple, and in the main can be described in terms of bond fission to form R₁R₂N⁺ or R₃R₄[graphic omitted]CO or 1–3 hydrogen rearrangement to form [R₁R₂NH][graphic omitted] or [R₃NCO][graphic omitted]. There is no evidence for the corresponding alkyl or aryl rearrangement.