Crop environment and weed interaction were assessed in miliet/cowpea and millet/cowpea/sorghum cropping systems under traditional and improved agronomic conditions in Che Sudan Savanna zone of Nigeria. The specific objectives of the experiment were to measure the effect of the intercropping on light transmission, assess the effect of intercropping on the soil and canopy temperature, and to quantity the effect of the intercropped environment on the type, yield ana frequency of weed growth, one variety of millet (EX bornu), two varieties of sorghum (1CSV-400 and Gaya Early) ana two varieties of cowpea (Dan-ilia and IT89KD-3/4) were used for this study in the intercropped combination. Two fertility levels (organic manure and inorganic fertilizer) were also employed. Microclimatological and plant indices measured include light transmission, soil temperature, canopy temperature, weed frequency, weed and crop shoot biomass. Results show that canopy temperature, soil temperature, and light transmission within the canopy were lower in the intercropped combinations than in the sole, weed dry weights were also lower on the average in the intercrops than in sole plots, although sole crops of millet and sorqnum were planted at a higher density than the intercrops, in intercropping combinations associated with sorghum, sorghum lCSV-400 was observed to be more efficient in suppressing weeds than the local Gaya Early variety, it was also observed that Digitaria horizontalis and Cyperus esculentus showed the hignest frequency of occurrence for both trials. This study indicates that controlling the weed regime of the cropping systems of the study area is dependent upon understanding the light reactions of these two notorious weeds.