The VUV photo absorption spectrum of acetone-d₆ is recorded in the energy region 6 – 10 eV using synchrotron radiation at are solving power of ~1000. Extensive Rydberg series are observed converging to its first ionization limit (9.708eV). Quantum defect analysis and vibronic analysis of higher Rydberg series members have been reported for the first time. A comparative study of the Rydberg series and accompanying vibronic structure observed in acetone-h₆ and acetone-d₆ has clarified and consolidated many of the vibronic assignments.The frequency of the ν_19^' mode(CO in-plane bend) of the 3p_y state is obtained as 340±75 cm^-1 on the basis of observation of an extensive progression of this mode.