The purpose of this work is to examine the accuracy of the DLPNO approximation for large van der Waals com-plexes. The most thorough previous effort along these lines is a recent study of double-hybrid DFT for transition metal compounds, where the localized-orbital technique was applied to the second-order Møller-Plesset (MP2) component of the double-hybrid energy expression. As compared to what is typical in thermochemical DLPNO-CCSD(T) calculations, tighter PNO thresholds were found to be required in order that the DLPNO-MP2 interaction energy remain faithful to the canonical MP2 result. Not addressed in that study is the performance of the DLPNO approximation in the presence of diffuse basis functions, which are the bane of linear-scaling approximations but are sometimes useful for obtaining converged intermolecular interaction energies. Systematic tests of the DLPNO approximation in large van der Waals complexes are missing from the literature and the present work aims to fill this gap, examining the accuracy of the DLPNO approximation as a function of molecular size for nanoscale complexes as large as (C 96 H 24 ) 2 , along with standard large-molecule benchmark data sets including L7 and S12L. Comprehensive testing for the S66 data set of smaller dimers is used to set a baseline. Because we need canonical results for comparison, we perform many of these calculations at the MP2 level rather than the CCSD(T) level, in basis sets ranging up to aug-cc-pVQZ, although CCSD(T) results are also presented for S66 and L7. Our results establish the accuracy that can be expected when the PNO thresholds are extrapolated to the canonical limit, and we examine the impact of diffuse basis functions on that extrapolation.