  The General Relativity affirms that any field is a source of gravitational
field, thus one should affirm that the energy of Cosmic Microwave Background
(CMB) generated primordial gravitational waves. The present article shows that
a gravitational wave with dimensionless amplitude $\sim 10^{-5}$ and large wave
length $\sim 10$ megaparsecs shifts temperature of CMB radiation about of a
part in $10^{5}$.
