The sentence was passed on Monday by a judge in Cordoba, Spain.
A nine-person jury declared Bretón guilty or murdering his children, Ruth, aged 6, and José, aged 2, in its verdict earlier this month.
The declaration came at the end of a protracted trial that gripped the imaginations of the Spanish public and fuelled intense media speculation.
Bretón had originally told police that he lost the two children in a park in October 2011.
But the jury learned that he had drugged them and burned their bodies to hide the evidence.