The proximate and ash constituents of twenty weed species have been determined. These weeds are all common to north‐eastern England. Some are characteristic of hedgerow and roadside and a few species of arable land; the majority, however, usually occur in pasture and meadowland, or in other sites where they are freely accessible to stock. Exact locality, approximate stage of growth and date of harvesting are recorded.A comprehensive examination of their ash has been made and four trace elements of recognized importance,viz. iron, manganese, copper and cobalt, were determined.The weeds have been classified on the basis of a marking system, and it was found possible to place them in one or other of three fairly well‐defined groups,viz. high, medium or low apparent value.Reference has been made to earlier assessments of these weeds and probable values, as reflected by chemical analysis, have been discussed. Most of the weeds listed as being of high apparent value are known or could justifiably be assumed to be of good nutritive status; examples of such are dandelion, nettle, creeping thistle and broad‐leaved plantain. Ragwort, although ranked highly on the marking system used, is well‐known to be toxic to animals. Not all members of the group of medium apparent value are likely to be eaten to any appreciable extent and at least two are of doubtful wholesomeness. Among weeds of low apparent value, only bird's‐foot trefoil would appear to have much potential u