The permeation properties of several self-compacting concretes ( SCC ) were compared with conventional vibrated concretes of the same strength grades as part of a systematic study to assess the durability of SCC mixes. SCC and conventional mixes of nominal crushing strengths of 40 and 60 MPa were prepared using Portland cement, continuously graded crushed granite, natural sand, fine limestone powder, superplasticisers and viscosity agents. The SCC mixes had significantly lower oxygen permeability and sorption compared with the vibrated concretes of the same strength grade. Chloride diffusivity was dependent upon the filler used - SCC mixes containing no additional powder but using a viscosity agent had considerably higher diffusivities than the reference mixes and other SCCs. 18 refs.