Finance Secretary Rajiv Mehrishi and other finance ministry officials have already reached Baku for the meeting of Board of Governors of the ADB.
The four-day 48th annual meeting of the ADB began today.
Jaitley, according to sources, is likely to return on May 5 and will be there in Parliament to pilot important economic legislations, including Goods and Services Tax and the black money bills.
He will also have to get the Finance Bill, 2015 approved in the Rajya Sabha. The Bill was passed by the Lok Sabha on Thursday.
The Manila-based ADB focuses on development in infrastructure, education, environment, regional cooperation and integration and finance sector development.
Established in 1966, it is owned by 67 members. In 2014, ADB assistance totalled USD 22.9 billion, including co-financing of USD 9.2 billion.