The peculiar magnetic properties of lanthanide(III) ions may be exploited for the development of powerful NMR probes for biomedical applications. Gd^III chelates are in current clinical use as contrast agents for magnetic resonance imaging. Other paramagnetic lanthanide(III) complexes endowed with shift reagent capabilities are used for the separation of NMR resonances of species present in the inner and outer cellular compartments and for the measurement of pH and temperature.