In this paper, we describe the speaker verification (SV) systems developed by Indian Institute of Technology Guwahati (IITG) for the NIST 2012 speaker recognition evaluations. The primary submission consists of five gender dependent SV systems combined at score level. Among the five systems two are based on sparse representation over learned and exemplar dictionaries, and the remaining are based on the generic i-vector and its variants obtained by vowel and non-vowel conditioning. The exemplar dictionary based system in particular exploits the new evaluation rule allowing the knowledge of all targets in each detection trial. The performance of the system is presented for the NIST SRE 2012 core task. © 2013 IEEE.