Controlling the interfaces between cells and materials is important subject for a wide range of research fields such as cell biology, tissue engineering, and biomedical devices. Here we report a novel electrochemical method to direct the adhesion and growth of mammalian cells on a substrate during cultivation in situ, named "Electrochemical Bio-Lithography". We found that the cell-repellent nature of the albumin- or heparin-coated substrates can be locally switched to cell-adhesive, by treatment with hypobromous acid electrochemically generated at the tip of the scanning microelectrode. Since this technique can be conducted under typical physiological conditions, we were able to direct cellular proliferation and migration by drawing adhesive micropatterns over the preexisting cellular pattern. The integration of this electrochemical system into a microfluiclic device will provide a novel type of cell-chip which enables on-demand immobilisation of cells just prior to the use of devices.