Baluchi sheep is the dominant fat-tail breed in Iran. We studied the microbial communities in the rumen of four Baluchi lambs fed a high concentrate conventional diet, the partial ribosomal rRNA of bacterial and archaeal were amplified by polymerase chain reaction (PCR) using DNA extracted from rumen samples. The amplicons were sequenced using 454 Titanium pyrosequencing and the data analyzed using the QIIME software package. The results indicated that Prevotella, a member of the phylum Bacteroidetes, dominated and its relative abundance accounted for 70.7 ± 2.68 % of the bacteria. Firmicutes was the second most abundant phylum, and Selenomonas and unclassified Veillonellaceae and Lachnospiraceae were present at relative abundances of 2.4 ± 0.62, 2.1 ± 0.21 and 1.9 ± 0.58 %, respectively. Entodinium was the most abundant genus of protozoa, comprising 61.6 ± 4.52 % of the protozoal community, followed by Polyplastron and Isotricha with relative abundances of 18.2 ± 2.35 and 9.7 ± 5.62 %, respectively. More than half of the archaeal community (53.3 ± 1.87 %) was composed of members of the Methanobrevibacter gottschalkii clade. The second and third most dominant archaea were members of the order Methanomassiliicoccales (28.3 ± 5.23 %) and Methanobrevibacter wolinii and relatives (8.5 ± 4.26 %). Based on this, rumen microbes of Baluchi lambs fed a total-mixed rations diet were similar to rumen microbes of ruminants fed similar diets in the other geographic regions around the world.