He was 74. Gaekwad is survived by wife Subhangini Devi, son Samarjeetsinh Gaekwad and two daughters.
Ranjitsinh died in the wee hours at the ICU of the local hospital where he was undergoing treatment for cancer of kidney, family sources said.
The ruler of the erstwhile princely state succeeded as the 'Maharaja of Baroda' after the death of his elder brother Fatehsinghrao Gaekwad in 1988.
He served two terms as Congress MP from Vadodara seat, first in 1980 when late Prime Minister Indira Gandhi offered him ticket and again in 1984.
Ranjitsinh enjoyed close ties with the Gandhi family, especially with Rajiv Gandhi and his wife Sonia, in whose honour he had hosted a dinner at his Laxmi Palace here in 1986.
A painter himself, Ranjitsinh was a connoisseur of art and had organised painting exhibitions at a number of places in India and abroad, including the UK.
