Tressa Montalvo welcomed the boys by Caesarian section at The Woman's Hospital of Texas in Houston on Valentine's Day.
Ace and Blaine were born at 8:51 a.m. weighing 3lbs 10oz and 3lb 15oz and Cash and Dylan arrived just a minute later - hitting the scales at just 2lbs 15oz and and 3lbs 6oz.
Tressa, 36 and her husband Manuel Montalvo Jr. started trying for a baby last year, so they could give two-year-old son Memphis a little brother or sister.
The couple were first told they were expecting twins when Tressa was 10 weeks pregnant.
The next time she visited her doctor, a third heartbeat was detected - and then a fourth.
After further scans experts told the Montalvos their babies weren't quadruplets, but two sets of identical twins - each set sharing one placenta.
According to previous reports, Dr. James Grifo, director of the NYU Fertility Center, has said the odds of having two sets of identical twins at the same time are 1 in 10,000 with in-vitro and much rarer with natural conception.