A preliminary survey on weedy rice infestation in rice fields was carried out during 2008 in all the rice producing states of the country including Jabalpur district and adjoining areas in Madhya Pradesh in particular. The study revealed that almost all rice fields were found heavily infested with weedy rice. The extent of infestation was found 5-60% in different states of India, whereas it was observed in the range of 11.32 to 44.28% in cultivators’ field and 0.78 to 2.40% at research farm of DWSR. Ten types of weedy rice (known as Sada or Sadwan) found in the farmers’ field and other two types found in water ponds / tanks (called as Pasai Dhan in Madhya Pradesh) were identified and characterized. Considering mean 10% infestation, the average loss in rice production was assessed to the extent of 9.15 million tones. The damage is likely to increase exponentially in subsequent years, if not managed effectively, challenging the rice production system in the country.