The invention relates to a device for injecting tire sealant fluid into a tire. The present invention uses a syringe type reservoir connected to a long, flexible tube which is in turn connected to a valve stem connector. The valve stem connector has two different threads, Schrader and Presta, to accommodate both types of valve stems. The Schrader type threads are larger than the Presta type threads and thus the Presta type threads are positioned further into the valve stem connector of the present invention than the Schrader type threads. The larger, Schrader type threads are used on automobiles and less expensive bicycles. The Presta threads are more common in Europe and are used on most high-performance bicycles. The main advantages of the present invention are that an exact amount of sealant can be dispensed, there is no wasted sealant because spillage is eliminated and the device uses no external power source to dispense the sealant. The tire sealant injector can be used on bicycles, utility vehicles, ATVs, lawn and garden tractors, wheelbarrows, golf carts and even automobiles.