A method for cell-based combinatorial logic includes the steps of providing at least one genetically engineered cell, the genetically engineered cell having at least one transcriptional unit. The transcriptional unit includes a gene and a promoter, wherein application of a stimulus to the promoter results in the expression of a gene product. An energetic or chemical stimulus is applied to activate the promoter, wherein the detection of an output signal corresponds to the presence of a gene product. The cell can include a plurality of transcriptional units configured to form logic gates. The logic gates of a plurality of cells can be operably interconnected by release of output signals, such as chemical stimuli.