We have analyzed the densities of the Uranian satellites derived from Voyager data to place constraints on their uncompressed densities and probable silicate mass fractions. Two bounding models were used: (1) a completely differential satellite with the current temperature/depth profile set by conduction of heat from the silicate core, and (2) a homogeneous model with the temperature profile also set by conduction. Results from such models for the largest satellites, Titania and Oberon, show that within the errors the silicate mass fraction of these two bodies should lie within the range 0.42--0.65, with the most probable values being 0.50--0.58. These values are significantly higher than similar model results for Saturn's small satellites (Rhea's silicate fraction is ~0.35--0.42) but similar to the system averages for Jupiter and Saturn (including Titan). The derived silicate fractions are also higher than predicted for solar nebular models having CH4 as the dominant carbon-bearing species. Examining current models of solar nebular chemistry and the three systems visited by Voyager, we suggest that the satellites accreted from material in the outer envelopes of their respective primaries, with the abundance of CO and solid organic material in the solar nebula and satellite-forming nebulae being important determinants of the rock/water ice ratios in these systems, and thus the satellite mean densities. Preferential dissolution of the water component of planetesimals in the envelopes of the giant planets may have also contributed to determining the water/rock fractions incorporated into the planets' satellites. ¿ American Geophysical Union 1987