The Raman spectrum of furfural has been obtained photoelectrically in the liquid over a temperature range of 50° and in solution. The infrared spectrum has been obtained for the solid, the liquid (over a temperature range of 90°), and in dilute solution over a 50° temperature range. The vibrational spectrum is interpreted in terms of an equilibrium mixture of two rotational isomers with planar configuration. The isomer with higher electric moment is the more stable form in the liquid and in the solid.