Process mining is the approach that extracts real workflows by database of events (logs) and compares them to the predefined procedures estimating the process gap for process improvement. It is a different overture from Data Mining that extracts hidden information and relations from data, with whom it is often confused. The most important tool for the development of process mining is ProM, an open source suite which implements a lot of technical approaches for process mining. This paper aims to present Process Mining approach showing the differences from Data Mining, and the implementation by ProM on real logs of an Italian company, comparing the extracted workflows to ISO9001 predefined procedures.