The present work refers to the one–step gas phase complete glycerol deoxygenation to propylene, under continuous flow conditions. The effect of the reaction parameters (temperature, hydrogen partial pressure P°H2, hydrogen to glycerol partial pressure ratio P°H2/ P°glyc, LHSV and W/F) was investigated over an 8.7 wt% molybdenum catalyst supported on black carbon. The main physicochemical properties of the catalyst (surface area, crystal phases, reducibility and thermal stability) in fresh, reduced and used form were determined. The extensive testing of the catalyst under variable reaction conditions proved the high activity of the catalyst in reduced state towards C-O bonds scission and more importantly, the high selectivity towards propylene which in most of the cases was the only carbon containing product in the gas phase. Partially deoxygenated liquid products were identified, such as 2-propenol, the intermediate for propylene formation along with its isomer propanal, and its hydrogenated form, 1-propanol. Response surface methodology was applied to examine the binary effects of process parameters (P°H2, P°H2/ P°glyc, LHSV and W/F) on the responses (propylene yield, propylene rate and combined yield of propanal and 1-propanol) followed by the optimization of the reaction. The empirical process models developed for each response accurately fitted the experimental data. The validation of the model showed that the experimental data at the proposed optimum reaction conditions were very close with the predicted ones, confirming its adequacy. Under optimum reaction conditions (P°H2 = 30 bar, P°H2/P°glyc = 80, LHSV = 1 h−1, W/F = 422 gcat/molglych, T = 280 °C and Ps =60 bar) glycerol is selectively converted to propylene achieving 71 % propylene yield (2 mmolesC3H6/gcath rate) at compete glycerol conversion.