Cyclobutyl methyl ketone (CMK, methyl cyclobutyl ketone) is an alicyclic ketone. It has been synthesized by reacting cyclobutanecarbonyl chloride with magnesium salt of malonic ester. The mechanism of the photochemical reaction of gaseous mixtures of cyclobutyl methyl ketone diluted in argon has been studied by steady-state and pulsed (laser) photolysis. It′s infrared (3500 to 30cm-1) and Raman (3200 to 30cm-1) spectra in gaseous and solid state has been recorded. The UV spectra have been measured in alcohol and isooctane solution. Study on the vapour phase thermal and photodecomposition of methyl cyclobutyl ketone shows that the mode of decomposition is free radical in nature.