Two field experiments were conducted at El-Serw Agricultural Re­search Station in North Delta, Egypt, during 1996 and 1997 seasons to study the possibility of sunflower relay cropping on transplanted toma­toes. A split plot design with four replications was used. The main plots were devoted to the time of sunflower cropping e.g., at transplanting (S1), flowering (52), and fruiting (S3) stages of tomatoes. The sub plots were devoted to sunflower populations (12000 and 24000 plants/fad'). Results indicated that sunflower-tomatoes relay cropping has some good advantages. The highest yield of tomatoes (20.3 tons/fad) + sunflower (980 kg/fad) were obtained when the high plant population of sunflower was relayed in the highest land equivalent ratio LER (2.10). While, the early cropping relay (S1) recorded the lowest yield in both crops (0.9 ton of tomatoes + 798 kg of sunflower/fad), the lowest LER (0.64) and the high( st sunflower competitive ratio (11.8).