Former Dallas Cowboys star Mike Jenkins was involved in a heated confrontation at a Florida bar over the weekend ... video obtained by TMZ Sports shows.

The incident happened at The Kenwood on Sunday night in St. Petersburg ... after Jenkins had apparently become upset with the way one of the establishment's employees had handled his credit card.

A witness tells us the worker had either misplaced or lost Jenkins' plastic -- which agitated the former 2008 NFL Draft first-round pick.

According to the witness, after making a scene inside the bar, Jenkins -- a University of South Florida alum -- then went outside and screamed at a security guard at the door.

In footage from the scene, you can hear the ex-defensive back drop cuss words left and right -- while insisting he did nothing wrong. Then, at one point, you can hear him yell, "Give me my motherf***ing card!"

A rep for the St. Petersburg Police Dept. tells us cops were dispatched to the bar at around 1:39 AM on Monday morning due to "a fight or disturbance." However, the spokesperson said no arrests were made. The rep added that Jenkins was issued a trespass warning -- and nothing more.

We've made multiple attempts to reach out to Jenkins for comment, but so far, we haven't heard anything back yet.

39-year-old Jenkins played in 71 games in his five seasons in Dallas -- and made one Pro Bowl in 2009. Following his time in Big D, he logged snaps with the Raiders and Buccaneers.