A computer system has been developed to add data acquisition, display, storage, and processing capability to a multiparamenter flow cytometer/sorter. The system can handle one or two parameters in histogram mode. Alternatively one, two or more parameters are stored event-by-event on an external storage device in list-mode with a resolution of 12 bit. The processor can also control cell sorting. Usual multichannel analyzer features are implemented in software, using standard interface boards without special electronics. Data are accepted via Direct Memory Access (DMA), which depends only on hardware. Data acquisition deadtime is nearly independent of software routines such as graphics display and interactive work. Since more than 8000 events/sec are achieved for eight paramenter handling, the computer system has capacity for rapid data acquisition. Although there is no need for such high data acquisition rates in present flow cytometry, it gives the advantage of short single event acquisition and longer process control handling.