We describe the first complete mitochondrial genome of Gelidium vagum (Gelidiales) (24,901 bp, 30.4% GC content), an agar-producing red alga. The circular mitochondrial genome contains 43 genes, including 23 protein-coding, 18 tRNA and 2 rRNA genes. All the protein-coding genes have a typical ATG start codon. No introns were found. Two genes, secY and rps12, were overlapped by 41 bp.
Keywords: Complete mitochondrial genome; Florideophyceae; Gelidiales; Gelidium vagum; rhodophyta.