The present invention provides a pneumatic injector that includes a pressurized gas source, an actuator, a driver, and a dispenser. The dispenser of the injector includes a reservoir for containing a desired amount of a chosen medicament and a needle, such as a hypodermic needle, suitable for subcutaneous, intramuscular, or intra-articular delivery of the chosen medicament. The actuator actuates the transmission of pressurized gas from the pressurized gas source to the driver, and as pressurized gas is delivered to the driver, the driver exerts at least an injection force. The injection force is of sufficient magnitude to expel a chosen medicament through the needle of the dispenser within a desired amount of time. Advantageously, the design of the injector of the present invention is extremely flexible, allowing the injector to be designed to deliver a wide range of medicaments in virtually any human or veterinary context calling for the injection of the subcutaneous, intramuscular, or intra-articular injection of medicament.