We developed an apparatus for inoculation of a large number of plantlets or plant parts such as shoots or roots into a large-scale fermenter at one time. Ab opa belladonna adventitious roots (2.4 kg FW) were inoculated into a 500 l fermenter under sterile conditions, and 35 kg FW of the roots were obtained after 60-d cultivation. There were no differences in proliferation rate and scopolamine content between a 10 l fermenter culture used as control and the 500 l fermenter culture. The success of large-scale root culture was considered to be dependent on the use of the new inoculation apparatus.