A two-stage, inclined continuous rotary torrefier with novel flights has been developed in the Biomass Conversion Laboratory at Dalhousie University for improving biomass torrefaction processes. Experimental work on torrefaction of small poplar wood particles (0.5-1.0 mm) in the torrefier was undertaken fijr a deeper understanding of the working of such torrefiers where the volatile gas released was used as the torrefaction medium instead of nitrogen. The rotary torrefier is operated under different operating conditions by varying its rotational speed; tilt angle and temperature. Measured chemical and physical properties of the torrefied products included ultimate and proximate analysis, structural analysis, energy density, mass yield, energy yield, and bulk density. A novel probe was developed to Wiled samples of biomass and measure temperature at different interior points along the length of the rotary torrefaction reactor while the biomass was being progressively torrefied in it. Axial temperature distribution of the rotary torrefier showed a parabolic profile but the fixed carbon content, volatile, and energy density of biomass undergoing torrefaction varied linearly along the length of the torrefier. For torrefaction at 300 C and 5 rpm and 1 of tilt angle the change in heating value was 40%, while the mass yield and energy yield of torrefied biomass were 34% and 48%, respectively. Results showed that temperature is the most irhpottant parameter in this torrefaction process.