- Barbados and Jamaica become members of the Bank.
- The Vatican assigns the management of its Populorum Progressio Trust Fund to the Bank, with the initial contribution being earmarked for agrarian reform in Colombia.
- First financing for specific components of construction of tourist hotels, benefiting Ecuador and Paraguay.
- Third Increase in Resources, for $3.5 billion: $2 billion for the ordinary capital (with $400 million payable in cash) and $1.5 billion for the FSO.
- Felipe Herrera resigns from the office of the president on October 11, effective March 1, 1971, to return to Chile.
- The governors elect Antonio Ortiz Mena President of the Bank on November 27, for a five-year term beginning on March 1, 1971.
- The research study paper commissioned to Raúl Prebisch to provide the IDB with a regional development outlook, Transformación y desarrollo: la gran tarea de América Latina (Transformation and Development: the Great Task of Latin America) is published.
- Norwegian Development Fund for the development of Latin America is created.
- Argentina becomes first borrowing member country to create a trust fund; to finance projects in Bolivia, Paraguay and Uruguay.
- $35 million loan to Peru for reconstruction after a devastating earthquake.
- Venezuela receives $75 million as the Bank's first financing for integrated rural development.
- First financing for the Andean Development Corporation (CAF), which was created in 1970; for project identification.
- First financing for the International Maize and Wheat Improvement Center (CIMMYT) and the International Center for Tropical Agriculture (CIAT) to support agricultural professional training.
- During its first 10 years of operations, the Bank approved $4..103 billion in loans benefiting the following sectors in descending order of size: agriculture, transportation and communications, manufacturing and mining, electrical energy, water and sanitation, urban development and housing, and education.
- One out of every four Latin Americans has directly benefited from IDB operations and an even higher proportion has benefited indirectly.
- Infrastructure-related loans (transportation, communications and electrical energy) increase, surpassing agriculture as the main beneficiary of operations.
- Antonio Ortiz Mena takes office as President of the Bank.
- First large loan targeted toward tourism development: $22 million for infrastructure in Cancún, Mexico.
- Bank charter amended to permit membership of Canada, IMF member countries from outside the Western Hemisphere, and Switzerland.
- Canada joins the Bank.
- Explicit policy adopted to grant preferential treatment to the less developed countries in operations with resources from the FSO.
- First binational project: $80 million loan for the Argentine-Uruguayan Salto Grande dam.
- Reorganization of the Bank, which entails the creation of the Office of the Controller and the Project Analysis Department and strengthening of the country offices.
- Volume of ordinary capital loans surpasses volume of FSO loans.
- Governors discuss accession to the Bank of Caribbean countries, which recently became independent, at their first Annual Meeting in an English-speaking Caribbean country, in Kingston, Jamaica.
- First loan for the fishing sector: $1.6 million to the Dominican Republic.
- Creation of the Swiss Fund for Technical Cooperation and Small Projects.
- Multisector loan for $16.7 million for the rebuilding of Managua after a devastating earthquake.
- Twelve nonregional countries sign the Declaration of Madrid, announcing their decision to become members of the Bank.
- First loans specifically earmarked for public health: $15 million to El Salvador and $5.3 million to Trinidad and Tobago for the construction and expansion of hospitals and other health care facilities.
- First large loan for fishing industry development: $43 million to Mexico and $3.5 million to Panama.
- First loan with significant components for preservation of cultural heritage and historical monuments: $29.8 million to Peru for tourist development in Cuzco and Puno.
- First loan, $1.5 million, for reforestation and forest protection, on more than 320,000 hectares in Nicaragua.
- Total annual amount of loans approved by the Bank reaches $1.111 billion, surpassing the $1 billion mark for the first time.
- Non reimbursable technical cooperation comes to $22 million, its highest annual level to date.
- Venezuela places a trust fund for $500 million under the administration of the IDB for the development and integration of Latin America.
- First complementary financings from international private banks as part of a program to mobilize private resources for Latin America and the Caribbean. They benefit a private Argentine steel mill, Acindar, and the hydroelectric project over the Chixoy river in Guatemala; this project receives $105 million in total financing, an unprecedented amount for Bank operations up until that time.
- Financing totaling $30 million for forest management and large-scale reforestation in Argentina.
- First financing for alternative energy sources: $500,000 for studies on geothermal energy in Costa Rica revealed that the source was feasible.
- Sharp increase in support to cooperatives in the region.
- Belgium, Denmark, Germany, Israel, Japan, Spain, Switzerland, the United Kingdom and Yugoslavia become members of the Bank. With their contributions the interregional capital is created adding these resources to the ordinary capital to form the total authorized capital.
- Guyana joins the Bank.
- Fourth Increase in Resources, for $4 billion to the authorized capital ($344 million payable in cash), interregional capital created with $502 million ($84 million payable in cash) as part of authorized capital, and $1.552 billion is added to the FSO. It is complemented in 1978 with the addition of $1.304 billion to the authorized capital.
- A $59.5 million loan for the largest industrial project in Central America to date, in the extensive pine forest in Olancho, Honduras.
- A $20 million loan and technical assistance provided to Guatemala for reconstruction after an earthquake.
- Technical cooperation for feasibility studies that support the creation in 1977 of the Latin American Export Bank (BLADEX), in Panama.
- Support to new Intraregional Technical Cooperation program.
- The Bank's aggregate lending exceeds $10 billion, with total project cost exceeding $43 billion.
- Austria, Finland, France, Italy, the Netherlands, Sweden and the Bahamas become members of the Bank.
- Bank charter amended to permit loans to the Caribbean Development Bank (CDB) for operations with member countries of the CDB, whether they belong to the IDB or not.
- First loan and nonreimbursable technical cooperation to the CDB.
- First loan from the interregional capital, for the equivalent of $13.9 million.
- First bond issues on the Japanese market, for the equivalent of $56.2 million.
- Board of Governors approves Fifth Capital Replenishment totaling $9.75 billion: $8 billionin authorized capital and $1.75 billion for the Fund for Special Operations.
- Governors decide that 50 percent of operations must benefit low-income groups, 20-25 percent must be for energy, including unconventional sources, 20-25 percent must go to external debt service reduction, and 5-10 percent must benefit projects designed to eliminate bottlenecks in economies.
- Startup of small projects program to benefit low-income farmers, artisans and small-scale businesses. First financing is for Manos del Uruguay, a women's wool-knitting cooperative.
- Largest loan to date, $210 million, for the binational hydroelectric plant Yacyretá, built by Argentina and Paraguay.
- Agreement with the International fund for Agricultural Development (IFAD) to channel resources to agricultural development projects.
- Disbursements reach $1.062 billion, surpassing for the first time the $1 billion mark in a single year. Accumulated disbursements reach $8.094 billion.