The density of liquid and undercooled Y3Al5O12 was measured over a wide temperature range with the help of an electrostatic levitation furnace. The density of a levitated droplet was measured with a ultraviolet-based imaging technique that illuminated the sample throughout all phases of processing, including at elevated temperatures. Over the 1470-2420 K temperature range, the density can be expressed as p(T)/(kg m(-3)) = 3.99 x 10(3)-0.29 (T - T-m)/K (5 percent) with T-m=2240 K, yielding a volume coefficient of thermal expansion alpha(T)=7.3 x 10(-5) K-1. (C) 2002 Elsevier Science B.V. All rights reserved.