The decision was taken at the annual meeting of the highest decision making body of the organization.
The distinctive loose khaki shorts have been an integral part of the RSS uniform for 91 years.
The RSS is the ideological mentor of India's ruling BJP, and Prime Minister Narendra Modi is a former member.
The organisation's general secretary Suresh Bhaiyyaji Joshi told reporters that the "major change" in uniform was because the organisation was "not rigid" and wanted to keep in step with modern times.
The PTI news agency quoted him as saying that there was no "specific" reason for changing the color of the uniform from khaki, except that brown was "commonly available and looks good".
The uniform change is expected to be fully implemented within the next six months.
Established in 1925, the RSS (also known as the Sangh) has been banned three times in post-Independence India.
Critics of the organisation say that the RSS (National Volunteers' Organization) is a sectarian, militant group, which believes in the "supremacy of Hindus" and "preaches hate" against Muslims and Christian minorities.
The Indian press is reporting that the RSS are going to shed their shorts once and for all in a bid to attract more young people.
The Indian Express quotes a senior "pracharak" - full time RSS worker - as saying that the two main leaders of the organization are in favor of a new dress code.
The plan is, the newspaper says, to replace the organization's breezy shorts with full length trousers.
"No, it hasn't suddenly decided to stop singing paeans to cow urine or denouncing beef", opines India's online news site, Scroll. "It's the khaki shorts, the leadership has decided. That's what's keeping the youth from signing up for early morning PT and minority bashing."