Aerosol particle detection and sizing techniques have recently been extended downwards to a size range commensurate with the size of many important biomolecules. Although such large molecules do not naturally occur individually as aerosol particles, electrospray-drying makes it Feasible to generate an aerosol of isolated single macromolecules from macromolecule solutions. The combination of this electrospray generation with the improved aerosol techniques makes possible a new method of size analysis for biomolecules. We present characteristics of this new system and review some recent results.