Fabrication of cellular spheroids is critical for creating functional tissue units and investigating the mechanism of tumorigenesis, development, and intercellular and cell–matrix interactions in vitro. Herein, we developed a novel, simple, and facile method for cell spheroid fabrication by using polyacrylamide/gelatin methacrylate (PA/GelMA) hydrogel composites. Arrays of Michigan Cancer Foundation-7 (MCF-7) breast cancer cell spheroids can be easily formed by tuning the GelMA composition. The shape and size of cell spheroids can be also well controlled by regulating cell seeding density and culturing time. All these results suggested that this simple and facile platform can serve as a useful tool to generate three-dimensional (3D) cell spheroids and can be integrated within high-throughput drug screening platforms, which will be of great help in engineering functional tissue models and regenerative medicines.