Background: Present study investigates the effect of adding nanoclay particles and foaming conditions on cellular properties of ABS/Nanoclay nanocomposite foams. Methods: For this purpose, first nanocomposite components are mixed using a twin-screw extruder. The amount of added nanoclay is considered 2 and 4 percentage by weight. Also, poly methyl methacrylate (PMMA) with the percentages of 2 and 4 wt% are used as the compatibilizer. Distribution of nanoclay particles in ABS matrix is examined using X-ray diffraction test. Then, nanocomposite samples are produced using injection molding process and foamed using batch foaming process. CO 2 gas is used as the physical blowing agent of the foaming process. The saturation time of samples and the effect of adding of nanoclay on CO 2 sorption/desorption rate was assessed by gravimetric method prior to foaming experiments. Then, nanocomposite samples are foamed under different process conditions according to a Taguchi L9 orthogonal array. Results: The obtained results reveal that adding nanoclay increases the cell density and decreases both foam density and cell size of ABS/nanoclay composite foams compared to the pure ABS foams. Conclusions: Results show that the structural properties of nanocomposite foams depend on both processing parameters and percentage of nanoclay in the nanocomposite specimens.