A novel haloalkaliphilic archaeon, strain B23(T) was isolated from the former lake Texcoco in Mexico. The strain was Gram-stain-negative, the cells coccoid to ovoid rods, red pigmented and aerobic. Strain B23(T) grew in 1.7-4.3 M NaCl, at pH 6.5-9.5 and at 25-45 °C with optimal growth at 2.6-3.4 M NaCl, pH 7.5-8.5 and 37 °C. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain B23(T) was most closely related to Natronobacterium gregoryi SP2(T) with 97.3 % sequence similarity. The polar lipids of strain B23(T) were phosphatidylglycerol and several unidentified phospholipids. The G+C content of the DNA of the strain was 62.5 mol%. Levels of DNA-DNA relatedness between strain B23(T) and Natronobacterium gregoryi DSM 3393(T) was 32.3 %. The name Natronobacterium texcoconense sp. nov. is proposed. The type strain is B23(T) ( = CECT 8068(T) = JCM 17655(T)).