Relating soil structure to soil hydraulic properties is an important issue for understanding and managing soil functioning. Fractal models were applied to relate soil water retention and soil structure. One such model developed by Rieu and Sposito (1991a) predicts an equality of (i) soil matrix fractal dimensions derived from 'aggregate bulk density- aggregate size data' and (ii) soil fractal dimensions derived from water retention. The objective of this work was to test the statistical hypothesis of such equality for model soil systems of packed soil aggregates. Typic Argiudol and Typic Argiaquol soils were sampled at eight locations that differed in long-term management practices. Soil water retention was measured at 12 levels of soil matric potential ranging from −1200 to −20 kPa. The 'aggregate bulk density-aggregate size' data were obtained for seven ranges of aggregate sizes from 0.25 to 16 mm. The statistical hypothesis about the equality of mass fractal dimension as derived from the aggregate bulk density data and the scaling dimension of water retention could not be rejected in our study.