Abstract: KNOX (KNOTTED-like homeobox) genes encode a class of homeodomain transcription factors, which play important roles in shoot meristem initiation and maintenance and lateral meristem morphogenesis. To reveal the functions of KNOX in tobacco, a KNATM1 gene was cloned from Nicotiana tabacum by homology search. The open reading frame of NtKNATM1 was 522 bp in length and encoded 174 amino acids. Bioinformatics analysis indicated that NtKNATM1 encoded a KNOX protein with an atypical domain, which contained KNOX1 and KNOX2 domains. Phylogenetic analysis showed that NtKNATM1 was close to Arabidopsis thaliana KNATM in evolutionary distance, and these genes formed a unique KNOX cluster. qPCR showed that NtKNATM1 was highly expressed in axillary bud and terminal bud. Auxin significantly up-regulated the expression level of NtKNATM1, in comparison with the down-regulation effect of topping. Therefore, NtKNATM1 might involve in the developments of shoot meristem and lateral meristem, and be positively regulated by auxin.