Brasses containing 20 and 30 pct Zn and up to 1.15 pct Be have been examined to provide tensile test data on the age-hardening response of these ternary alloys. It was found that yield strengths of 1100 Mpa were attainable with cold working prior to aging at 300°C. The mode of precipitation, as determined by electron micros copy and electron diffraction, agrees substantially with recent work on the binary Cu-Be system. Precipitation commences as GP zones on the (001)α planes. The observed precipitate phase, after aging times of up to seven days at 400°C, is CuBe with an orientation relationship of the type (301)ppt ∥(113)α [010]ppt ∥[110]α.