A device for single cell analysis by determining the presence and/or amount of one or more target molecules in a plurality of cells, comprising: (i) a solid substrate configured for immobilizing thereon a plurality of said cells in the form of a monolayer, the cells being spaced apart from each other on said substrate to allow the position of each individual cell to be determined; (ii) a computer-assisted microscope stage for determining the position of the individual immobilized cells on the solid substrate relative to a reference point on the solid support or relative to each other, the computer having a program that can recognize cells and assigns a positional identifier to each cell by determining/calculating the coordinates, e.g. x/y coordinates, of each cell's center and storing said coordinate data as well as the cell size; (iii) a signal detector for measuring the auto-fluorescence of the individual immobilized cells; (iv) the device being configured for use with a first detection reagent for contacting the immobilized cells, said reagent comprising (a) a moiety that specifically recognizes and binds a first target molecule and (b) a fluorescent label under conditions that allow binding of the detection reagent to the first target molecule; (v) the computer program being configured for measurement of the fluorescence of the fluorescent label of the detection reagent bound to the first target molecule for the individual immobilized cells; (vi) the computer program being further configured to detect the presence and/or amount of the first target molecule in the individual immobilized cells by comparing the fluorescence measured in step (v) with the fluorescence measured in step (iii) on a cell-by-cell basis; and (vii) the device optionally being configured for use with a second or further detection reagent comprising (a) a moiety that specifically recognizes and binds a second or further target molecule and (b) a fluorescent label, the computer program then being configured to repeat steps (iv) to (vi) with the second or further detection reagent. (i) a solid substrate configured for immobilizing thereon a plurality of said cells in the form of a monolayer, the cells being spaced apart from each other on said substrate to allow the position of each individual cell to be determined; (ii) a computer-assisted microscope stage for determining the position of the individual immobilized cells on the solid substrate relative to a reference point on the solid support or relative to each other, the computer having a program that can recognize cells and assigns a positional identifier to each cell by determining/calculating the coordinates, e.g. x/y coordinates, of each cell's center and storing said coordinate data as well as the cell size; (iii) a signal detector for measuring the auto-fluorescence of the individual immobilized cells; (iv) the device being configured for use with a first detection reagent for contacting the immobilized cells, said reagent comprising (a) a moiety that specifically recognizes and binds a first target molecule and (b) a fluorescent label under conditions that allow binding of the detection reagent to the first target molecule; (v) the computer program being configured for measurement of the fluorescence of the fluorescent label of the detection reagent bound to the first target molecule for the individual immobilized cells; (vi) the computer program being further configured to detect the presence and/or amount of the first target molecule in the individual immobilized cells by comparing the fluorescence measured in step (v) with the fluorescence measured in step (iii) on a cell-by-cell basis; and (vii) the device optionally being configured for use with a second or further detection reagent comprising (a) a moiety that specifically recognizes and binds a second or further target molecule and (b) a fluorescent label, the computer program then being configured to repeat steps (iv) to (vi) with the second or further detection reagent.