This report describes the results of applying the computer-assisted image analysis system for the measurement of some cytological parameters of LPS-stimulated and nonstimulated human monocytes. The experiments were carried out by means of the digital cell image analysis of haematoxilyn stained monocytes. Five different parameters describing the morphology of monocytes and their nuclei were selected to quantitate the differences between control and activated cells area, perimeter, elongation, dispersion, and extension of images of cell projections. The results suggest that all of the analysed parameters can be used to discriminate stimulated from nonstimulated monocytes which permits detailed monitoring of the changes in cell morphology during monocyte activation.