AbstractJapanese knotweed, Fallopia japonica (Houtt.) Ronse Decr., (Polygonaceae), is a serious environmental and economic weed in its adventive range of Europe and much of North America. Such is the scale of the problem in the UK that a pioneering biocontrol programme began in 2003 which would possibly make it the first target of a full classical biological control of weeds programme in Europe. This paper summarizes the current status of the plant, reviews the literature associated with its natural enemies and reports the progress with the programme for UK sponsors, as well as referring to North American interests. We conclude that, should appropriate permissions be made available, the prospects for biological control of this high profile weed, using arthropod and fungal agents, are good.