Five Far-Infrared (50-600 cm-1) spectra are presented: the sodium and potassium salts of 5' Guanosine Monophosphate (GMP), each salt in both the gel and crystal conformations, and poly(rG). Measurements were performed at a sample temperature of 10 K under vacuum with a liquid He-cooled bolometer. The spectra were fit with Lorentzians and assignments are suggested. There are noteworthy differences in oscillator strengths and frequencies of the bands between all spectra. We report the tentative observation of a 100 cm-1 mode which is in the neighborhood of a mode observed by Raman spectroscopy in solution (1) and dried gels (2).