Two field trials were carried out at Shandaweel Research Station (Sohag governorate) during 2005 and 2006 summer seasons to investigate the response of groundnut to intercropping with three sesame varieties under different plant densities in relation to yield and yield component of both crops. A split plot design with three replicates was used. The main plots were devoted to sesame varieties (Shandaweel 3, Toshka 1 and Giza 32) while the sub plots were devoted for plant densities (100%, 67% and 50% representing three hill spacing of sesame i.e. 20, 30 and 40 cm. respectively). The groundnut (the main crop) was grown on all ridges at a normal plant density. The data obtained indi-cate that all studied traits of groundnut were de-creased when intercropping with sesame varieties as compared with solid crops. This reduction was higher when intercropped with sesame cv Giza 32 than with the other sesame varieties. Yield and yield components of groundnut were also signifi-cantly affected by the plant densities of sesame varieties. The yield of groundnut when inter-cropped with low sesame density (50%) exceeded that with high density of sesame (100%) by 31.66, 27.51 and 29.53 % in the first, the second and the combined of the two seasons respectively. The results also indicated that yields of all sesame va-rieties were decreased under intercropping condi-tion. Sesame Giza 32 variety surpassed the other varieties (Shandaweel 3 and Toshka 1) in plant height, number of branches, number of capsules / plant, seed yield / plant and seed yield / fad. The high plant density (100%) recorded the highest sesame seed yield / fad. where the increase was 46.93 and 13.50 % in the first season, 2.46 and 8.71% in the second season and 25.86 and 11.19% in the combined data over the low and medium density treatments, respectively. The re-sponse equations of pod yield / fad. of groundnut was linear with each decrease of sesame planting density and with higher magnitude under Toshka 1 than under the other to sesame varieties. The treatment of groundnut with Toshka 1 under low density had higher land equivalent ratio (LER) (1.41), intercropping advantage (IA) (582.8) and monetary advantage index (MAI) (1666.85). The treatment of groundnut with Giza 32 under low density had higher actual yield loss (AYL) (+1.245). It could be concluded that intercropping groundnut with Toshka 1 under medium density had favoured the growth and yield of both crops.