Technetium-99m radiopharmaceuticals will continue to have a significant impact in several areas of nuclear medicine. This publication is intended to provide a broad overview of the current status of technetium-99m radiopharmaceuticals. It includes chapters on the most advanced chemical techniques for labelling biomolecules and synthesizing suitable multifunctional ligands that will help in the development of specific radiotracers. Of special interest for the reader are details of recent research to develop technetium-99m tracers for monitoring different biological processes enabling the development of new radiopharmaceuticals with greatly improved clinical potential.