The basic elements of a mitotic cell-finding machine are described. The hardware components comprising the machine are a motor-controlled microscope, a vidicon scanner and associated video-signal processor, and a digital computer. By very rudimentary signal processing, it is possible to derive an analog voltage from the camera video which is proportional to the amount of “speckled image” characteristic of metaphase cells at low magnification. A digital computer is used to control the microscope movement and to digitize the signal-processor analog output. Microscope slides prepared from human blood cultures are used in all the experiments. The results of a pilot experiment designed to measure the “speckled image” voltage for image features within a 100 µ by 100 µ field of view are discussed and extrapolated to the expected machine performance at larger and necessarily more complicated fields of view. It is expected that when conditions are set such that no usable metaphase cell image is missed by the machine, 50 % of the images scored will be usable, where a usable cell is one from which a karyotype could be obtained. Secondary picture processes for final selection of usable cells at high magnification are postulated, and it is estimated that the first- and second-stage searching processes together will give rise to an average cell finding rate of approximately 9 sec/cell. An experimentally tested automatic-focussing technique using the vidicon camera system is discussed.