In the present research work dimensional accuracy (Δd) of Al-Al2O3 based metal matrix composite (MMC) developed by combining stir casting with ABS replica based investment casting (IC) process has been highlighted. Three controllable factors of the IC process, namely: layer combination (LC), material composition (MC), pouring temperature (PT), were studied at three levels by Taguchi's parametric approach along with fixed parameters of stir casting process and single-response optimization was conducted to identify the main factor controlling Δd. Ceramic shell moulds were made on ABS plastic patterns (prepared by FDM process) using primary slurry and fused-silica sand as stucco. The final MMC prepared by stir casting process has been poured in these moulds. Finally results of study highlights the percentage contribution of different input parameters for Δd of MMC prepared by combined stir casting and IC process.