The influence of primary and secondary nucleation on multiplicity behavior of agglomeration-controlled crystallization in a continuous isothermal mixed suspension-mixed product removal crystallizer is analyzed by use of bifurcation theory. The criteria for uniqueness and multiplicity of steady states for both primary and secondary nucleation are derived, and the multiplicity boundaries only dependent on the physical and kinetic properties and operational parameters of the process are obtained. The number of steady states in the crystallizer for various multiplicity regions is determined, and the linear stability of these steady states is analyzed.