The aircraft are scheduled to be delivered between October 2012 and December 2014 subject to regulatory approvals, the company said in a filing to Bombay Stock Exchange.
The agreement is aimed at maintaining and expanding its international and domestic operations using B737 NG aircraft, it said.
The company, under the purchase agreement, has also taken the option of acquiring an additional ten Boeing 737-800 series aircraft, it said.
These ten aircraft are scheduled to be delivered between August 2013 and February 2015, it said. The last of the ten B737NG aircraft, previously ordered by the company are scheduled to be delivered on October 11, 2007 and there are no unused delivery positions for B737NGs available till October 2012, it said.
The shares of the company dropped 0.97 per cent to Rs 932.40 on the BSE.