The new sesquiterpenoid 8-deoxy-15-(3'-hydroxy-2'-methyl-propanoyl)-lactucin 3'-sulfate (1) was isolated from the methanolic extract of roots of Reichardia gaditana L. The compound was isolated by silica gel column chromatography (CC) and repeated Sephadex LH-20 CC. Structure elucidation was accomplished by high-resolution mass spectrometry and by 1D- and 2D-NMR spectroscopy. The chemosystematic significance of the new compound is discussed in the context of sesquiterpenoids from other members of the Lactuceae tribe of the Asteraceae family.