The incorporation of a nitrated pentaerythritol additive selected from theono-, di-, tri-, and tetra-nitrated pentaerythritols into hydrazine is effective in lowering the freezing point of the combination while enhancing the performance of the monopropellant by contributing to the total energy of the monopropellant combination. Hydrazine content varies from about 65 to 95 weight percent while the additive of a nitrated pentaerythritol varies from about 5 to about 25 weight percent. An optional additional additive of methyl alcohol from about 5 to about 20 weight percent can be employed with a corresponding adjustment in weight percent of hydrazine when said additive of methyl alcohol is employed in addition to said additive of said nitrated pentaerythritol.