Abstract: The hemagglutinin of Gallibacterium genomospecies 2 strain CCM 5976 was purified by affinity to Glutaraldehyde-Fixed Rabbit Erythrocytes (GFRE) using trypsin-treated bacteria. Two protein bands of approximately 23 and 26 kDa were consistently observed using 12% SDS-PAGE. Other protein bands were also associated to GFRE but disappeared when heated up to 120°C while the hemagglutinating activity remained. Hemagglutinating activity by Gallibacterium was not inhibited by mannose or other carbohydrates tested yet both proteins and carbohydrates were consistently found in samples of purified hemagglutinin. These findings suggest that the Gallibacterium genomospecies 2 hemagglutinin is a glycoprotein-like molecule consisting of at least two subunits of 23 and 26 kDa and that are thermostable, trypsin-resistant and mannose-resistant.