In response to the need for a live histogram display for routine setting up of our new home-grown flow cytometer, an inexpensive and simple pulse height analyser has been built up from standard, readily available integrated circuits. Salient features include inbuilt analog to digital conversion, 1024 channels of 12-bit memory organised in four segments, a single display marker with readout of channel number and generation of both histogram and two-parameter dot plot displays. Inputs required are the analog held signals and a logical trigger pulse for each cell detected. The 33 I.C.s of the device are mounted on a single 166mm X 114mm "International" card with switching and the three-digit numerical display mounted on a shared, 88mm wide front panel.