A 2-year field study was conducted from 2001 to 2003 using common vetch (Vicia sativa) and oats (Avena sativa) in mixtures and pure stands, on a low-input basis, to investigate the effects of mixed cropping on yield and quality of forage as well as land equivalent ratio (LER) and competitive ratio (CR) of the component crops. Mean dry matter yield of pure oats was 6.07 t/ha and that of pure vetch was 4.14 t/ha (P<0.05), with the highest yield (6.32 t/ha) in the 45:55 oats: vetch mixture. Crude protein (CP) concentration in harvested dry matter increased as level of vetch in the mixture increased, with 8.5% CP in pure oats and 22.3% in pure vetch. CP yield peaked (1.1 t/ha) in the 45:55 oats: vetch mixture. Common vetch was a more competitive crop than oats in all mixtures except for 25:75 and 15:85 oats: vetch mixtures. It appears that a 45:55 mixture with low fertiliser level would produce as much forage as pure oats but of a higher quality than oats.