This paper proposes an ultra lightweight cipher ANU. ANU is a balanced Feistel-based network. ANU supports 64 bit plaintext and 128/80 bit key length, and it has total 25 rounds. It needs only 1015 gate equivalents for 128 bit key length that is less as compared with all existing lightweight ciphers. Its memory size is minimal, and power consumption is very less. It needs only 22mW of dynamic power, while PRESENT cipher consumes 39mW of power. This paper furnishes the complete security analysis of the ANU cipher design. Our security analysis shows that ANU can attain ample security level against linear and differential cryptanalysis, biclique attack, zero-correlation attack, and algebraic attack. Biclique cryptanalysis provides maximal data complexity of 2(64). ANU cipher not only needs less gate equivalents but also it consumes very less power and has less memory requirement. ANU cipher is best suited for applications like Internet of Things. The design of ANU cipher will have a positive impact in the field of lightweight cryptography. Copyright (c) 2016 John Wiley & Sons, Ltd.