An orthorhombic phase of Mn[sub 2]Sb (a = 0.562 nm; b = 0.432 nm; c = 0.757 nm) was obtained for the first time in the manganese antimonide samples treated at a pressure of P = 7 GPa and a temperature of T = 1800 K. The high-pressure phase is metastable under normal conditions and breaks on heating above 420 K. A characteristic feature of this phase is the absence of a total magnetic moment at T > 90 K.