In a leaf flavonoid survey of 59 specimens of the Winteraceae and related families, representing nine genera, luteolin 7,3'-dimetbyl ether (in 77%) and flavonols (in 81%) were found to be major constituents. Indeed the high incidence of luteolin 7,3'-dimetbyl ether chemically isolates the family from all other angiosperm groups, including families and genera that have been taxonomically associated with the Winteraceae in the past. Simple flavones (in 16%), on the other band, were found only in some Drimys s. str., Tasmannia and Pseudowinteru species. Similarly, the distribution of flavone C-glycosides was restricted to specimens of T. piperita and one specimen of D. winteri. The frequent occurrence of procyanidin (in 60%) and dibydroquercetin (in 44%) reflects the primitive and woody nature of the family. The combined flavonoid data clearly support previous cytological, morphological and pbylogenetic studies in the division of the Winteraceae into three groups of genera: (1) Bubbia, Belliolum, Exospermum and Zygogynum; (2) Drimys s. str. and Pseudowintera and (3) Tasmannia. Some generic variations were found within the Bubbia, Belliolum, Expospermum and Zygogynum group but apart from minor geographic variations within Belliolum the flavonoid results do not appear to provide suitable evidence for subgeneric taxonomy.