The magnetic and structural properties of Cu-Mn-Al alloys with 39-44 at.% Cu, 21-28 at.% Mn and 30-37 at.% Al have been investigated. As-cast alloys show the presence of a Heusler phase and FCC Al. The relative proportion of the Heusler and Al phases is approximately the same for all alloys. The X-ray line intensities indicate that the hysteretic properties of the alloys, particularly the coercive force, Hc, and (MH)max, are related to the chemical ordering of the Heusler phase. The alloy Cu42Mn25Al33 has the highest Hc of any as-cast alloy, 1630 Oe. The effects of annealing on this alloy have been investigated. Beginning at 568K, Al4Cu9 precipitates from the Heusler structure. This causes a significant increase in Hc and a corresponding decrease in the saturation magnetisation Ms. At 708K, additional Al4Cu9 precipitates with a drastic decrease in both Hc and Ms. The properties of the Heusler composition Cu2MnAl are discussed for comparison.