Introduction of Bt cotton in 2002 in Central and Southern zone and in 2005 in North came as a boon to the cotton farmers. Field trials showed that Bt cotton is effective in against boll worms and in improving yields. The average increase in yield from Bt cotton varied from 45 to 63 per cent. Area under Bt cotton increased from 0.5 million hectares in 2004 to 3.8 million hectares in 2006-07. New problems are  emerging with the plantation of Bt cotton under North Indian conditions.  These are increased incidence of sucking pests, susceptibility to leaf curl virus, bad opening of bolls and Para wilt. Late sowing, frequent irrigations, optimum use of nitrogen fertilizersly and use of growth retardants at  boll development stage may brings reduction in  Tirak.  Application of Cobalt chloride during 36-48 hours after irrigation to Para wilt affected plants helped in complete recovery within 5-7 days. Efforts should be made to discourage the cultivation of illegal Bt and sowing of F₂ and spurious seeds for harvesting maximum fruits from Bt technology.