We have sequenced and described the mitochondrial genome of Thecamoeba quadrilineata (Amoebozoa, Discosea, Thecamoebida). This is the first sequenced mitochondrial genome for amoebae of Thecamoebida lineage. The circular mitochondrial DNA of this species has 50942 bp in length and contains 23 protein-coding genes, 2 ribosomal RNAs, 18 transfer RNAs, and 26 open reading frames. In contrast with the shorter mitochondrial genomes of vannellid amoebae, it shows no evidence of RNA editing. This finding supports the hypothesis on the multiple origins of editing in different phylogenetic lineages of Amoebozoa.