The influence of the addition of cement kiln by-pass dust on the physicomechanical properties of alumina cement on cooling as well as after firing at 1200 degreesC and 1300 degreesC was studied. Results show that the water of consistency as well as setting time increase with the addition of cement dust both on cooling and firing. Where as mixing alumina cement with cement dust affects adversely on the specific properties of the cement, the properties are improved on firing at 1300 degreesC. The free CaO content of cement dust is partially utilized by alumina cement on cooling, but further utilization occurs on firing. The XRD analysis revealed that by firing of alumina cement together with cement dust, new calcium silicate and aluminate phases are formed, which are responsible for the relatively higher rate of hydration. Accordingly, the physicomechanical characteristics of the cement are improved.