A new iridoid diester (1R,2S,6S,9S)-5-acetyloxymethyl-9-methyl-3-oxabicyclo[4.3.0.]non-4-en-2-yl isovalerate), which we have named valdiate, was isolated from the hairy roots of Valeriana officinalis var. sambucifolia Mikan transformed with Agrobacterium rhizogenes R1601. It was characterized by its chemical and physical data. Together with valdiate, five valepotriates were isolated and identified by means of mass spectrometry and 1H and 13C NMR spectrometry. The analysis of the non-transformed plant roots belonging to the same species, indicated the absence of valdiate and the presence of four valepotriates only.