The reaction of organomercury(II) halogenides (RHgHal, Hal = Cl, I) with silver azide furnished the corresponding covalent organomercury(II) azides RHgN3 (R = Me (1), tBu (2), Ph (3)). In addition to the characterization by multinuclear NMR spectroscopy, IR and Raman spectroscopy as well as mass spectrometry, the mercury content was determined. A dependance on the solventpolarity for the 14N NMR resonances was observed. Furthermore, X-ray diffraction studies were performed and the crystal structures for mercury(II) azides 1–3 are reported. A comparison of the bond lengths and angles with data from theoretical calculations is given.