The Prime Minister also handed over the Organic Certificate to Chief Minister Pawan Chamling here.
"Sikkim has paved its way into history and has set an example to the entire world that nature needs care and protection", he told the National Conference on Sustainable Agriculture & Farmers' Welfare at Chintan Bhawan here.
Congratulating the state in Nepali, he said it will soon become the harbinger of organic farming not only in country but around the world.
The prime minister was welcomed by Governor Srinivas Patil and Chief Minister Chamling who were accompanied by cabinet ministers and heads of all state government departments.
People from all walks of life thronged the highway since morning to get a glimpse of Modi. They shouted welcome slogans and waved flags and flowers.