Metal Matrix Composites (MMC) are composites with at least one metallic constituent material. These materials generally have desirable qualities such as high strength-to-weight ratio, high toughness, lowvalue of coefficient of thermal expansion, high wear resistance, and thermal stability. They are therefore increasingly finding applications in areas that require these qualities such as in aerospace, automotive, millitary, biological and nuclear energy fields. The application of these materials usually require them to be machined to a high accuracy and to have a good surface finish. These materials are hard and abrasive, making it difficult to machine using conventional processes such as drilling and grinding. To address these challenges, electrical discharge machining (EDM) can be used. This paper investigates the effect of low frequency vibration in EDM machining of aluminium silicon carbide (AlSiC) MMC using oil and deionised water as the dielectric fluids. Experiments were carried out on AlSiC (AMC225XE) material using Sarix-100 high precision micro-erosion machine, with and without workpiece vibrations. For the experiments with vibrations, a vibration frequency of 900Hz was used. The results of this study indicate that introduction of vibration increases the material removal rate (MRR), results in an inferior surface quality and improves dimensional accuracy regardless of the dielectric used. It was also seen that the use of deionised water as the dielectric results in higher MRR as compared to the use of oil dielectric. In addition, machining using oil dielectric results in higher dimensional and geometric accuracy than machining in deionised water.