Na10(Na,Mn)7Mn43(PO4)36 (sodium manganese phosphate) was synthesized hydrothermally at 873 K and 0.35 GPa. The complex crystal structure is almost identical to that of natural fillowite-type phosphates and can be described as a hexagonal packing of three types of rods parallel to the c axis. The rods are constituted by an alternation of five- to seven-coordinated Mn sites [average Mn-O = 2.243 (3) A], of six- to nine-coordinated Na sites [average Na-O = 2.590 (3) A], of PO4 tetrahedra [average P-O = 1.548 (3) A] and of cation vacancies.