Two field experiments were conducted at Mallawi Agric.Res.Station during two successive seasons of 200212003 and 2003i'2004 to study the effect of ridges width (60 and 120 cm) different planting densities of onion (33 and 66%) on the root and bulb yields of sugar beet and onion . The experimental design was split plots with four replications. The important results could be summarized as follow:- Yield and yield components of sugar beet were higher when grown on narrow ridges (60 cm) than under wide ridges (120cm).yield and its components of onion were higher under wide rides than those grown on narrow ridges . The reduction in intercropped sugar beet yield with high onion population  density (66.6%) were higher than with low population density (33.3%).The reduction percentage were 16.6 and 35.8% for root diameter,23.2 and 40% for root weight as well as 12.0 and 31.3% for root yieidlfed .Bulb diameter and bulb weight of onion were higher under low density than high onion density, while bulb yield was reduced under low onion density . The highest value for L.E.R was 1.46 when intercropped on wide ridges with high onion population density, While the total in come reached to 4316.5 L.E when intercropped with low onion density on narrow ridges. It can be concluded that intercropping sugar beet (100% density) with low onion density (33%) on narrow ridges (60 cm) could be recommended which increased economic income (13.46%) per unit arua without effect on the quality and productivity of sugar beet .