  The upper main sequence stars CU Virginis is the most enigmatic object among
magnetic chemically peculiar (mCP) stars. It is an unusually fast rotator
showing strictly periodic light variations in all regions of the
electromagnetic spectrum, as well as spectroscopic and spectropolarimetric
changes. At same time, it is also the first radio main-sequence pulsar.
Exploiting information hidden in phase variations, we monitored the secular
oscillation of the rotational period during the last 53 years. Applying own
phenomenological approach, we analyzed 37\,975 individual photometric and
spectroscopic measurements from 72 data sources and improved the O-C model. All
the relevant observations indicate that the secular period variations can be
well approximated by the fifth degree polynomial.
