The lovebirds were supposed to get married on Saturday at a city administrative building, but suddenly the 50-year-old groom, who suffers from hypertension, started to feel ill outside the building, El Pais reported.
Madrid emergency services reported on Twitter that the man was feeling dizzy and sick.
Family members called for an ambulance and at first paramedics waited to see if his condition would improve, according to El Pais. But when it didn't, they decided to take him to hospital.
But despite his condition, the woozy groom insisted that he marry his bride in the ambulance before going to the hospital.
“The man felt a bit overwhelmed. I told him that they could get married another day, but he insisted. The truth is that the paramedics told me that it wasn't a serious case and the transfer to the hospital could be delayed for a few minutes,” said Madrid councilwoman Esther Gómez.
So Gómez hopped into the ambulance and performed the civil ceremony with the wedding guests looking on through the ambulance door.
“Usually I read them a poem, but in this case I was only limited to reading the articles of the civil code,” the councilwoman said.
They even threw rice and shouted “long live the newlyweds” once all the official documents had been signed.
“The emergency services of Madrid are always needed, in sickness or in health,” wrote Gómez later on Twitter.
The groom was then taken to hospital to recover from the dizzying day.