A Debenture, in which no time is fixed for the company to pay back the money, is an irredeemable debenture.

According to Rule 18(1)(a) Companies (Share Capital and Debentures) Rules, 2014 an issue of secured debenture may be made for a period of redemption not exceeding ten years from the date of issue. In case of certain companies such redemption period may exceed ten years but not exceed thirty years.

After the commencement of the Companies Act, 2013, no company either public or private can issue perpetual or irredeemable debentures.