Shortly after midnight Saturday, police officers went to the Londontown Pub after a stabbing had been reported.
Police said a suspect, Roberto Garcia, 64, of Riva, was taken into custody at the bar. They also confiscated a knife believed to have been used in the fight.
Police said the altercation began when the victim offered a man a drink in what they called a friendly gesture. Police said the man then began to punch and stab the victim. Another patron struck the man and knocked him down. Police said a knife was taken away from him.
The victim, whose name was not released, was taken to Maryland Shock Trauma Center with life-threatening injuries.
The suspect was taken to Anne Arundel Medical Center with facial injuries. Garcia has been charged with attempted murder, assault and other charges.