The present invention provides stable, ready-to-use injectable pharmaceutical compositions, comprising the combination of neostigmine, glycopyrrolate, a stabilizing amount of one or more aminopolycarboxylic acids, and a pharmaceutically acceptable liquid vehicle. Other aspects of the invention relate to methods for making such compositions and methods of using such compositions for reversing the effects of non-depolarizing neuromuscular blocking agents. Preferably, the composition comprises neostigmine methylsulfate, glycopyrronium bromide, ethylenediaminetetraacetic acid (EDTA) and a pharmaceutically acceptable liquid vehicle, and is provided in a pre-filled, ready-to-use sealed container, such as a pre-filled syringe, suitable for intravenous administration.