Human PrP (huPrP) is a high-affinity receptor for oligomeric Aβ. Synthetic oligomeric Aβ species are known to be heterogeneous, dynamic and transient, rendering their structural investigation particularly challenging. Here, we used huPrP to preserve Aβ oligomers by coprecipitating them into large hetero-assemblies to investigate the conformation of Aβ(1-42) oligomers and huPrP in the complex by solid-state MAS NMR spectroscopy. The disordered N-terminal region of huPrP becomes immobilized in the complex and therefore visible in dipolar spectra without adopting chemical shifts characteristic of a regular secondary structure. Most of the well-defined C-terminal part of huPrP is part of the rigid complex, and solid-state NMR spectra suggest a loss in regular secondary structure in the last two αhelices. For Aβ(1-42) oligomers in complex with huPrP, secondary chemical shifts reveal a substantial β-strand content. Importantly, not all Aβ(1-42) molecules within the complex have identical conformations. Comparison with the chemical shifts of synthetic A fibrils suggests that the Aβ oligomer preparation represents a heterogeneous mixture of -strandrich assemblies, of which some have the potential to evolve and elongate into different fibril polymorphs, reflecting a general propensity of Aβ to adopt variable β-structure conformers.