A 2-year neld study was conducted to compare the influence of harvesting datrs on agronomie characteristlcs, forage yield and quality of four winter rye (fecafe cereofe L.) cultivars at the experi-mental fold of Livestock Farm, College of Agriculture, Seoul National University, Suwon.All rye rultlvars were winter hardy. Winter more and Elbon were upright in growth and early inmaturity with tall plant height, while Korean native and Kodiak were semi-prostrate and prostrate,respectively in growth and later in maturity with shorter height.Dry matter yields of Winter more and Elbon were significantly higher those of Korean native andKodiak harvested in early In 1985 and 1986. There were no slgnincant differences in dry matter yieldof the rye cultivars harvested in late in 1985, but Winter more and Elbon were signifcantly higherforage yield than the two other cultivars harvested in late in 1986.Crude protein (CP) concentrations of Korean native and Kodiak were signifcantly higher thanthose of Winter more and Elbon harvested in both early and late in 1986.There were no significant differences in tu uifro dry matter digestibility (IVDMD) of the rye col-tivars harvested in early in 1986, but those of Korfan native and Kodiak were signiHcantly lligher thanthe two other cultivars harvested in late.CP and IVDDM yields of Winter more and Elbon were significantly higher than those of Koreannative and Kodiak harvested in early in 1986. but no signiFcant differences were round among the ryeco]tivars haryested In late.