Our understanding of the detailed mechanisms of specific promoter/enhancer DNA-binding site recognition by transcriptional regulatory factors is primarily based on three-dimensional structural studies using the methods of X-ray crystallography and NMR. Vast amount of accumulated experimental data have revealed the basic principles of protein-DNA complex formation paving the way for better modeling and prediction of DNA-binding properties of transcription factors. In this review, our intent is to provide a general overview of the three-dimensional structures of DNA-bound transcriptional regulators starting from the basic principles of specific DNA recognition and ending with high-order multiprotein-DNA complexes.