Version 2.2 data acquisition software from PicoQuant GmbH is available for the company’s PicoHarp 300 time-correlated single-photon-counting system. The software provides driver support for the 64-bit versions of Windows Vista, and it supports control for other monochromator models, enabling automated recording of time-resolved emission spectra. It includes an online correlater for fluorescence correlation spectroscopy, which is useful for setting up and monitoring related experiments. The user interface has been redesigned to provide better visualization of measurement data. The PicoHarp is based on a time digitizer with 4-ps resolution and a processing rate of up to 10 million counts per second.