Machine stoppage directly affects the production capacity of the plant. Among the breakdowns with greatest impact on production capacity are those related to bearing and gear failures in the machine's mechanical transmissions. Good monitoring not only prevents serious breakages in the machine, but can also optimise the use of the bearings and increase the availability of the machine. This article presents an analysis of the most common bearing failures, the various monitoring techniques are reviewed that can be used for the diagnostic of failures in ball bearings and, lastly, an automatic bearing diagnostic tool is presented, which can monitor and diagnose the condition of the analysed bearing. Through this monitoring, failures in bearings can be detected from their initial phase, and their evolution can be seen up to the final phase of the useful life of the bearing. The information generated during the monitoring is very useful both for the manufacturer and for the end user of the machine. In the case of the former, it allows the manufacturer to correct possible design and/or assembly faults, while in the case of the latter, it allows the end-user to prevent breakages and to plan machine stoppages to carry out maintenance.