The infrared (3500 to 50 cm−1) and Raman (3200 to 10 cm−1) spectra have been recorded for the gaseous and solid states of cyclopropylcarbonyl fluoride, c‐C3H5CFO. Additionally, the Raman spectrum of the liquid has been recorded and qualitative depolarization values have been obtained. The asymmetric torsion for the conformer which has the carbonyl group cis to the cyclopropane ring has been observed at 88.5 cm−1 in the far infrared spectrum of the gas with five accompanying hot bands, and the corresponding torsion of the trans conformer was observed at 91.0 cm−1 with two additional hot bands occurring at 90.6 and 90.2 cm−1. From these data the potential function for internal rotation of the asymmetric top has been determined and the following potential constants have been evaluated: V1=−618±6, V2=1970±27, V3=399±6, and V4=−48±10 cm−1. It has been determined that the cis conformer is the predominant form at ambient temperature in the gas phase and the enthalpy difference between the cis and the trans confo...