Cell suspension cultures are rapidly dividing homogenous suspensions of cells grown in ltqutd nutrient media from which samples can be precisely removed (1). Cell suspensions are used for generating large amounts of cells for quantitative or qualitative analysis of growth responses and metabolism of novel chemicals, as well as for studies of cell cycle under standard conditions (2,3). In addition, cell suspensions serve as an ideal material for the isolation of protoplasts used in transient gene expression assays and Agrobacterzum— mediated transformation (4,5). The establishment of suspension cultures of Arabidopsis thalzana cells derived from leaf and hypocotyl calli has been reported (6). In order to mitiate Arabzdopsis suspensions retammg a high regenerative potential, a procedure described by Ford (7) has been modified Callus tissues derived from root or hypocotyl explants of Arabzdopszs yield well proliferating cell suspensions capable of morphogenesis m liquid medium. The regeneration capability and genetic stability of suspension cells, however, decrease by the length of culture period Therefore, it is recommended to use newly initiated cell suspensions when the applications require the regeneration of dtplotd fertile plants The method described is used to establish morphogenic cell suspensions from the Arabidopszs ecotypes Columbia, C24, RLD, and Wassilewskila. Slight modification of the concentration of growth regulators (e.g., auxm) and/or the time of subcultures may be required for other ecotypes.