Ancient cultivated tetraploid wheats (Triticum turgidum spp.) are known to be a good source of resistance to wheat stem rust, caused by Puccinia graminis f. sp. tritici (Pgt). A collection of 918 accessions of cultivated emmer (T. turgidum ssp. dicoccum), Persian (T. turgidum ssp. carthlicum), Polish (T. turgidum ssp. polonicum), Oriental (T. turgidum ssp. turanicum), and Pollard (T. turgidum ssp. turgidum) wheat was evaluated at the seedling stage for reaction to Pgt races with broad virulence, including TTKSK (Ug99), TRTTF, and TTTTF. Two hundred five (22.3%) accessions resistant to race TTKSK, were further evaluated for reaction to Pgt races virulent to different alleles of the Sr13 gene, including JRCQC, TTRTF, GCCDC, and TCMJC, and six additional US races. The presence of functional alleles of Sr13 (Sr13a and Sr13b) in the TTKSK-resistant accessions was postulated based on the seedling reaction against the selected Pgt races and by using molecular markers diagnostic to Sr13 haplotypes (R1, R2, and R3). Sr13 was postulated to be present in all T. turgidum subspecies except T. turanicum. Accessions resistant to all Pgt races evaluated and not carrying functional alleles of Sr13 will be further studied for the identification and characterization of new stem rust resistance genes. Since cultivated T. turgidum subspecies share the same genome as durum wheat, resistance genes could be easily transferred to durum by conventional breeding approaches.