B5 medium has been defined for the growth of cell suspensions of soybean root cells in the presence of 2,4 D. Nitrate was required in a concentration of 20-30 mM. An addition of 2 mM ammoniumsulphate led to an increase in cellgrowth. NH4+ when added as the sole source of nitrogen, did not support growth. Similar results were obtai-ned when NH4NO3 was substi-tuted for (NH4)2SO4. However, ammonium ions depressed growth when the concen-tration excee-ded 2 mM. Variati-ons in the concentrations of phosphate, calcium and magnesi-um resulted in relatively minor chan-ges in growth rate. Thiamine is known to be an essenti-al nutrient for cell growth and is increa-sed in concentrati-on up to 10 mg/l. B5 medium has been defined for the growth of cell suspensions of soybean root cells in the presence of 2,4 D. Nitrate was required in a concentration of 20-30 mM. An addition of 2 mM ammoniumsulphate led to an increase in cellgrowth. NH4+ when added as the sole source of nitrogen, did not support growth. Similar results were obtai-ned when NH4NO3 was substi-tuted for (NH4)2SO4. However, ammonium ions depressed growth when the concen-tration excee-ded 2 mM. Variati-ons in the concentrations of phosphate, calcium and magnesi-um resulted in relatively minor chan-ges in growth rate. Thiamine is known to be an essenti-al nutrient for cell growth and is increa-sed in concentrati-on up to 10 mg/l.