The other two MoS -- Subbirami Reddy and Dinsha J Patel -- have been accommodated in the ministries of mines and petroleum and natural gas respectively.
Ramesh has been in charge of the economic cell of the AICC and a member of the National Advisory Council
The portfolios of the three MoS have been allocated by President A P J Abdul Kalam on the advice of Prime Minister Manmohan Singh, Rashtrapati Bhavan spokesman S M Khan said.
With this, only Oscar Fernandes, who was inducted as MoS with independent charge, is still without a portfolio.
In the first major expansion-cum-reshuffle of his 20-month-old UPA government on Sunday, Dr Singh had accommodated 19 ministers and elevated three MoS to Cabinet rank.