A series of hybrid and pure density functionals have been assessed in order to provide a reliable description of infrared spectra of alkyl mercury compounds. The theoretical assessment also includes other physicochemical properties, as ionization energies and binding energies. The accuracy of the results was tested through the available experimental data and CCSD(T) calculations. B3LYP functional provides the smallest average error of all functionals considering the whole set of properties, and it offers very good results in IR spectra in particular, although other functionals as BP86, M06-L or mPW1PW91 can give even better results when looking at one particular property. Hybrid functionals B3PW91 and X3LYP and double-hybrid B2PLYP follow B3LYP in the list of most well-behaved functionals.