Global biotech giant Monsanto says its sales of genetically modified cotton seeds in India so far this year are more than double the figure for 2004.
BT cotton is the only genetically altered crop allowed in India.
A Monsanto spokeswoman said the 131% jump vindicated Indian farmers' faith in genetically altered cotton seeds.
Environmental activists have opposed Monsanto's attempts to market its products in India over the years.
Critics say GM crops have not been studied adequately and could harm the environment, a charge the firm denies.
India's cotton industry plants all types of cotton seeds on more than 7.9 million hectares a year.
Fight against pests
Monsanto said it had sold more than three million packets of genetically modified cotton seeds in India so far this year, compared to last year's figure of 1.3 million packets.
A company spokeswoman, Ranjana Smetacek, told the BBC the rise in sales was due to new varieties of seeds and to take up of the seeds by new states in 2005.
"This year, we have sold 20 different hybrids of BT cotton seeds, as compared to four varieties last year, and we made a major breakthrough in three northern Indian states - Punjab, Haryana and Rajasthan," she said.
BT stands for bacillus thuringiensis, a bacterium which enhances the resistance of cotton seeds to attacks from boll worms, which are a major problem in India.
BT cotton is the only genetically altered crop allowed in India, the BBC's Rajan Chakravarty says.
Critics say the GM seeds could contaminate the genes of conventional crops, leading to loss of biodiversity.
They also fear the prospect of foreign control over the country's food supply and say the cost of the GM seeds outweighs the profits they yield.
Monsanto has faced angry protests in India
Each packet of BT cotton seeds cost $40, nearly four times the price of conventional seeds.
Ms Smetacek said a survey by international market research firm IMRB in April this year backed Monsanto's claims that farmers using BT cotton seeds achieved considerably higher profits.
Monsanto, based in the United States, has licensed the BT cotton technology to 19 Indian partners, which have introduced 20 varieties and have submitted another 100 for approval by regulators.
The Indian government has delayed approval of some of the company's products and even banned some varieties of seeds.