The seizure of 0.006 pounds of the opioid happened on May 11 at the Bridge of the Americas border crossing, U.S. Customs and Border Protection wrote in a statement released on Tuesday.
A drug-sniffing canine alerted agents to something more on the 40-year-old woman, prompting a pat-down search.
Once that was completed, though, the woman went ahead and revealed what she hid.
"The female voluntarily removed a condom filled with fentanyl pills from her vaginal cavity," the CBP release read.
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The woman, who was not identified, was turned over to local authorities.
The seizure comes in the wake of recently released CDC data that counted a record 107,000 U.S. overdose deaths last year.
The arrest was one of 25 made by the federal agency in a week span at El Paso-area ports of entry that also included seizures of cocaine and methamphetamine.
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