Forty-six cultivars in eleven perennial grass species were assessed in association with subterranean clover in five trials extending over two to four growing seasons. Established stands of several phalaris and cocksfoot cultivars yielded more sown grass herbage and total herbage than Wimmera ryegrass, Australia Commercial phalaris and Currie cocksfoot. The highest yields were from C.P.I.19331 phalaris and G1 35 cocksfoot. G135 was also more resistant than Wimmera ryegrass to the invasion of older stands by barley grass. The herbage yield of the perennial grasses was more stable between years and trials than that of Wimmera ryegrass. The probable utility of these cultivars in the wheat belt and in the adjacent higher-rainfall pastoral zones is discussed.