A tissue dissociation method and system for washing and dissociating tissue and producing a cellular suspension for use in autologous, cell-based therapies or research wherein a sterile environment is maintained. More particularly, a system for dissociating tissue comprising a housing unit, a first compartment having a plurality of pores providing for fluid communication between the interior of the first compartment and the interior of the housing unit, a first inlet port that provides communication between the exterior environment and the interior of the first compartment and thereby provides a means for introducing solutions into the interior of the first compartment, a second compartment, a second inlet port for introducing a tissue sample into the system, a means for agitating or rotating the second compartment in the housing unit, a means for controlling the exit of effluent from the housing unit, a first receptacle, and a centrifuge-ready second receptacle for collecting a resulting cell suspension. The method comprises introducing a tissue sample into the system and subjecting it to a washing phase and a dissociating phase wherein the tissue is agitated or rotated. The tissue may also be subjected to a sedentary phase and a phase in which a solution is added to the resulting cell suspension to cease tissue dissociation. At the conclusion of the tissue dissociation process, the resulting cell suspension is collected in a centrifuge-ready receptacle.