Assessment of the quality of cytogenetic preparations is important for 1) a general quality control of the cytogenetic laboratory and 2) for determining the quality of individual cytogenetic analyses. It is generally accepted that good preparations allow a more detailed search for structural abnormalities than poor preparations. As part of a comprehensive study on automated assessment of slide quality we have developed a simple algorithm for automated measurement of metaphase resolution. During semi-automated karyotyping with the Magiscan chromosome analysis system (Joyce-Loebl) three measurements related to resolution are automatically extracted 1) the total number of dark bands of the chromosomes of the metaphase (TB), 2) the normalized average length of the chromosomes (NL), and 3) the average "thickness" of the chromosomes (T). The algorithm TB x NL/T has been tested on 35 metaphases of various quality and compared with visual assessment of the same 35 metaphases. The results indicate that the automatic assessment of metaphase resolution is superior to the visual.