Source: TMZ.com BestofMMA.com

Floyd Mayweather Jr. got hammered by a judge, who just sentenced him to serve 90 days in jail for beating up his baby mama in front of their kids.

Floyd was sentenced to 6 months in jail, but 3 months of that sentence was suspended.  He also gets 3 days credit for time he has already served.

TMZ broke the story … the boxer was arrested in September 2010 — after his ex-girlfriend accused him of striking her “multiple times in the head with his fist” and then threatening to kill her.

Floyd struck a plea deal with prosecutors in the case — in which he pled guilty to misdemeanor domestic violence … in exchange for getting a pass on the felony battery charge.

Floyd also pled no contest to two misdemeanor harassment charges — after allegedly threatening to beat his kids too during the incident.

The judge was especially pissed that Mayweather struck his baby mama in front of their kids.