A binary mixture of particles is utilized to investigate size-induced and non-size-induced axial segregation in a rotating drum using deformable 1 mm rubber particles as the key component. In the size-induced segregation studies, the dimensionless band width (width of segregation band divided by particle size) of the small particles (WB/d(p)) increases in proportion to the rotational speed in the range of 10 rpm to 40 rpm when the fill level is between 10% and 36%. WB/d(p) increases as the fill level increases from 10% to 36% with a particle size ratio 2 and has a maximum value with a particle size ratio 3. In the non-size-induced segregation studies, segregated bands are observed in (3 mm rubber-3 mm glass) and (4 mm rubber-4 mm glass) systems with low fill levels. There is no axial segregation when 1 mm and 2 mm rubber particles are mixed with 1 mm and 2 mm glass particles, respectively. The non-size-induced segregation bands were different from the size-induced segregation bands. The bands are less pure and the interfaces are less distinct. The results suggest that trajectory segregation is the dominant segregation mechanism in axial segregation in drums. (c) 2006 Elsevier B.V. All rights reserved.