A method for genetic transformation of lisianthus by co-cultivation ofin vitro grown leaves withAgrobacterium tumefaciens is described. Two strains, A281 and EHA105, both carrying the plasmid pKIWI105 capable of expressing the GUS gene were used in preliminary tests. A281 had higher transformation efficiency in terms of transient and stable expression. The efficiency of the strain EHA105 could be improved by including 2iP in co-cultivation and selection media, but never reached that of the oncogenic strain A281. An expression cassette containing the nucleoprotein gene of TSWV, carried by a binary plasmid, was introduced into EHA105 and used to transform lisianthus. After transformation and regeneration, the potentially useful transgene was present in seven plants derived from independent events of transformation and the presence of the transgenic protein was detected in one of them