This paper provides a summary of the Agglomeration and Size Enlargement session of the First International Particle Technology Forum held in Denver, CO, USA, August 17-19, 1994. The conference was sponsored by the recently formed Particle Technology Forum of the American Institute of Chemical Engineers. This first session on agglomeration and size enlargement brought together a cross-section of industries dealing with agglomeration processes. Represented were the areas of mineral processing, consumer products, ceramics, industrial chemicals, agricultural chemicals and fertilizers, biological materials, and pharmaceutical processing. The session focused on agitative granulation techniques including pan, fluidized bed, drum, and mixer granulation as well as compaction processes including tabletting, uniaxial compaction, and roll pressing. Two critical themes running throughout the session were (i) relating particle and formulation properties such as friction, plasticity, interfacial energy, and binder viscosity to bulk agglomeration behavior, and (ii) the incorporation of these relationships into process scale simulations. The aim of this endeavor was to share our different approaches to agglomeration processes and through this sharing achieve a cross-fertilization of ideas. It is hoped that this effort, and similar sessions to follow, will increase our understanding of agglomeration phenomena which can be utilized for the rational design and optimization of size enlargement processes as well as product design. This review paper summarizes the technical papers presented at this session as well as the subsequent discussion which followed (B.J. Ennis (ed.), Proc. Ist Int. Particle Technology Forum, Vol. i, American Institute of Chemical Engineers, New York, pp. 155-286).