A syringe-to-syringe mixing apparatus comprises first and second syringes adapted to be coupled at their respective outlets to fluidly connect the syringes. The first syringe includes a plunger having a hollow plunger barrel and a distal end defining a lumen therethrough. The lumen is initially closed by a septum, which in one embodiment is an elastomeric stopper mounted over the end of the plunger. The mixing apparatus further includes a third syringe slidably disposed within the plunger barrel. The third syringe includes a hollow needle adapted to pierce the septum to allow fluid from the third syringe to be injected into fluid within the coupled first and second syringes.