"As we devote ourselves to take India's development journey to newer heights, we seek your support, blessings and active participation," Modi said in his first message on the website.
He added, "Together we will script a glorious future for India. Let us together dream of a strong, developed and inclusive India that actively engages with the global community to strengthen the cause of world peace and development."
A short profile was also uploaded on www.Pmindia.Nic.In which described him as "dynamic, dedicated and determined" leader who "arrives as a ray of hope in the lives of a billion Indians".
It said that his "laser focus on development and his proven ability" to deliver results have made him one of India's most popular leaders.
Without naming the RSS, it said that from a very young age, Modi immersed himself in service to the nation, working with "patriotic organisations".
An option called "Wish the Prime Minister" takes a user to Modi's personal website.