Multimodal bioprobes, which integrate the advantages of different diagnostic modes into one single particle, can overcome the current limitations of sensitivity and resolution in medical assays and significantly improve the outcome of existing therapeutics. Lanthanide-doped inorganic multimodal bioprobes, which are emerging as a promising new class of optical/magnetic multimodal bioprobes, have been long sought-after and have recently attracted revived interest owing to their distinct optical and magnetic properties. In this concept article, we introduce the controlled synthesis of lanthanide-doped inorganic multimodal bioprobes, including core-shell structured and single-phase nanoparticles, and demonstrate different design strategies for achieving dual-modal functionalization of nanoprobes. In particular, we highlight the most recent advances in biodetection, bioimaging, targeted drug delivery, and therapy based on these nanoparticles.