The study was conducted to determine the response of soybean to a commercial herbicide mixture- Galex 500EC a. influenced by variety and seed size. Treatments consisted of four soybean varieties TGX 1448 2E, TGX 1455 2E, TGX 1458 2E and TGX 1497 1p each sorted into three seed size groups of small 9.6000 seeds medium 13.3e 100 seeds and large 15.3000 seeds and subjected to two herbicide rates 0 and 3Kg. a. alter ,Galex 500EC. The experiment was laid out in split split plot, randomized complete block design OWED. With three replications. Results show that significantly plant establishment count 65.3percent was observed with the large size seeds compared to the small size seeds values averaged over two herbicide rates. There were significant variety X Seed size interactions for days to first flowering, nodulation count, and number of pods per plant and number of seeds per pod. The interactions were however not significant for seed weight. TGX 1448 2E had the highest P less than 0.05 grain yield when planted with the large size seeds 2inder the herbicide treatment. Averaged over three seed sizes and two herbicide TGX1448 2E had the highest P less than 0.05 grain 1.11 tons per ha compared to other varieties. TGX 149 7 ID was the poorest, with total grain yield of 0.40tonsAa yield average over three seed sizes and two herbicide rates It is concluded that when Galex 500EC is to be used to control weeds in soybean field, the variety and size of soybean seeds should be considered.