The pure rotational spectrum of 2,2-bis(trifluoromethyl) oxirane has been recorded using a chirped pulse Fourier transform microwave spectrometer. A total of 317 transitions have been recorded and spectroscopic constants have been determined for the first time. Quantum chemical calculations suggest that at equilibrium the two CF3-groups have a slightly staggered configuration with respect to one another. However, the barrier to an eclipsed configuration is calculated to be very low, approximate to 10 cm (1). Arguments are presented suggesting that the zero-point energy of the molecule is above the barrier to the CF3 eclipsed structure such that the zero-point geometry can reasonably be described as possessing eclipsed CF3-groups. (C) 2012 Elsevier B. V. All rights reserved.