CONSTANS-like (COL) genes play important regulatory roles in flowering, tuber formation and the development of the potato (Solanum tuberosumL.). However, theCOLgene family inS. tuberosumhas not been systematically identified, restricting our knowledge of the function of these genes inS. tuberosum. In our study, we identified 14COLgenes, which were unequally distributed among eight chromosomes. These genes were classified into three groups based on differences in gene structure characteristics. The COL proteins ofS. tuberosumandSolanum lycopersicumwere closely related and showed high levels of similarity in a phylogenetic tree. Gene and protein structure analysis revealed similarities in the exon–intron structure and length, as well as the motif structure of COL proteins in the same subgroup. We identified 17 orthologousCOLgene pairs betweenS.tuberosumandS. lycopersicum. Selection pressure analysis showed that the evolution rate ofCOLhomologs is controlled by purification selection inArabidopsis,S.tuberosumandS. lycopersicum.StCOLgenes showed different tissue-specific expression patterns.StCOL5andStCOL8were highly expressed specifically in the leaves of plantlets.StCOL6,StCOL10andStCOL14were highly expressed in flowers. Tissue-specific expression characteristics suggest a functional differentiation ofStCOLgenes during evolution. Cis-element analysis revealed that theStCOLpromoters contain several regulatory elements for hormone, light and stress signals. Our results provide a theoretical basis for the understanding of the in-depth mechanism ofCOLgenes in regulating the flowering time and tuber development inS. tuberosum.