The decisions were taken during the first bilateral meeting between Prime Minister Narendra Modi and President Dilma Rousseff here.
In a special gesture, the host rolled out the red carpet and received Modi, who is not here on a bilateral visit, with full military honours at the Presidential Palace before their meeting over breakfast.
As leaders of G4 countries, Modi and Rousseff called for urgent progress on reforms of the United Nations, including the Security Council, by the time of the 70th anniversary of the UN in 2015.
The G4 nations comprising Brazil, Germany, India, and Japan are four countries which support each other's bids for permanent seats on the United Nations Security Council.
Modi and Rousseff also agreed to intensify their cooperation in international forums and multilateral institutions including the G20.
The External Affairs Ministry in a statement said the two leaders agreed to take steps to further expand and diversify trade and investment flows and deepen cooperation in agriculture and dairy science, convention and renewable energy, space research and application, defence, cyber security and environment conservation.
Bilateral trade between India and Brazil stood at USD 9.4 billion last year with balance of trade in favour of India. There have been two-way investments between the two countries and total FDI by Indian companies in Brazil from 2007 to 2013 was USD 0.1 billion.
The three agreements signed in the presence of Modi and Rousseff related to cooperation in the field of environment, space and in the establishment of a consultation mechanism on mobility and consular issues.
The agreement on space was made for implementing arrangement establishing cooperation in augmentation of a Brazilian earth station for receiving and processing data from Indian Remote Sensing (IRS) Satellites.
Modi congratulated Rousseff and the people for excellent conduct of the FIFA World Cup and the successful organisation of the BRICS Summit besides arranging a meeting of BRICS leaders with their counterparts from South America here.
He described the sixth BRICS Summit as a historic one which had produced two important agreements over the New Development Bank and the Contingency Reserve Arrangement and lauded the host for her guidance during the summit.
The Prime Minister described Brazil as a key global partner for India.
He noted that as two democracies and major emerging economies, India and Brazil not only had a vast potential for bilateral cooperation but also to strengthen each other in international forums and advance the interests of the developing world at large.
Modi also noted that Gujarat had emerged as a prime driver of India's economic relations with Brazil.
President Rousseff emphasised the special place this relationship enjoyed in Brazil's foreign policy, because of the potential for bilateral cooperation and the international significance of their partnership.
She congratulated Modi for his impressive victory in the election and wished him all success for India's progress and development.
The two leaders recalled the historical and cultural ties between the two countries, despite the distance, including the Gir cows that were brought to Brazil from India and the textiles and the fruits that came from India to Brazil in the 18th and 19th centuries.
Later in the day, the Prime Minister attended a working session of the BRICS Summit with South American leaders followed by a lunch.
President Rousseff invited leaders from South America including those from Argentina, Venezuela, Ecuador, Peru, Uruguay, Paraguay on the lines of President Jacob Zuma inviting those from Africa during the last year's summit in Durban.