Weedy rice belongs to the same genus and species as cultivated rice but with different forms. It appears as hybrid swarms due to introgression of genes between wild and cultivated species in nature. In Asian rice, it is known as Oryza sativa  var. spontanea whereas in African context it is said as O. sativa var. stapfii. It grows faster; produces more tillers, panicles and biomass; makes better use of available N; shatters earlier; has better resistance to adverse conditions; and possesses longer dormancy in soil. Because of its high competitive ability, it becomes a serious threat to rice growers worldwide. Great morphological variability, similar growth behavior and high biological affinity with cultivated varieties make its control difficult. No single management technique can effectively control weedy rice. An appropriate combination of preventive, cultural, mechanical and chemical control measures is essential.