In a dystopian near future, the city of Detroit is on the brink of societal and financial collapse. Overwhelmed by crime and dwindling resources, the city grants the mega-corporation Omni Consumer Products (OCP) control over the Detroit police force. OCP Senior Vice President Dick Jones demonstrates ED-209, a law enforcement droid designed to supplant the police. ED-209 malfunctions and kills an executive, allowing ambitious executive Bob Morton to introduce the Chairman ("The Old Man") to his own project; RoboCop.
Meanwhile, officer Alex Murphy is transferred to the Metro West precinct. Alongside his new partner Anne Lewis, Murphy pursues notorious criminal Clarence Boddicker and his gang. Murphy is ambushed and tortured by the group—Emil Antonowsky, Leon Nash, Joe Cox, and Steve Minh—until Boddicker shoots him in the head. Morton has Murphy's corpse converted into RoboCop, turning him into a powerful and heavily-armored cyborg with no memory of his former life. RoboCop is programmed with three Prime Directives: serve the public trust; protect the innocent; uphold the law; a fourth directive is classified.
RoboCop is assigned to Metro West and hailed by the media for his brutally efficient campaign against crime, but Lewis grows suspicious that he is Murphy from the unique way he holsters his gun—a trick Murphy learned for his son. During maintenance, RoboCop experiences a nightmare of Murphy's death. He leaves the station and encounters Lewis, who addresses him as Murphy. While on patrol, RoboCop arrests Emil; he recognizes Murphy's mannerisms, furthering RoboCop's recall. RoboCop returns with Emil to Metro West, and uses the police database to identify his associates and Murphy's police record. RoboCop recalls further memories while exploring Murphy's former home, his family having moved away following his death. Elsewhere, Boddicker murders Morton at Jones' behest for attempting to usurp his position.
RoboCop tracks down the remaining Boddicker gang and a shootout occurs. He brutally assaults Boddicker who confesses to being in Jones' employ. RoboCop attempts to kill Boddicker, until his programming directs him to uphold the law. He attempts to arrest Jones at OCP Tower and Directive 4 activates, a failsafe to neutralize RoboCop when acting against an OCP executive. Jones admits his culpability in Morton's death and releases an ED-209 to destroy RoboCop. Although he escapes, RoboCop is assaulted by the police force at OCP's order and badly damaged. Lewis helps RoboCop escape to an abandoned steel mill to repair.
Angered by OCP's underfunding and short-staffing, the police force goes on strike and Detroit descends into chaos as riots break out throughout the city. Jones frees Boddicker and his remaining gang, arming them with high-powered weaponry to destroy RoboCop. Boddicker's men are quickly eliminated, but Lewis is badly injured and RoboCop becomes trapped under steel girders. Even so, he kills Boddicker by stabbing him in the throat.
RoboCop confronts Jones at OCP Tower during a board meeting, revealing the truth behind Morton's murder. Jones takes The Old Man hostage and is promptly fired from OCP, nullifying Directive 4 and allowing Robocop to shoot him; he crashes through a window to his death. The Old Man compliments RoboCop's shooting and asks his name; he replies "Murphy".
Peter Weller as Alex Murphy / RoboCop:
A Detroit police officer murdered in the line of duty and revived as a cyborg.
Nancy Allen as Anne Lewis:
A tough and loyal police officer.
Dan O'Herlihy as The Old Man:
The chief executive of OCP.
Ronny Cox as Dick Jones:
The Senior Vice President of OCP.
Kurtwood Smith as Clarence Boddicker:
A crime lord in league with Dick Jones
Miguel Ferrer as Bob Morton:
An ambitious OCP junior executive responsible for the "Robocop" project
In addition to the main cast, Robocop features Paul McCrane as Emil Antonowsky, Ray Wise as Leon Nash, Jesse D. Goins as Joe Cox, and Calvin Jung as Steve Minh, members of Boddicker's gang. The cast also includes Robert DoQui as Sergeant Reed, and Felton Perry as OCP employee Donald Johnson. Mario Machado and Leeza Gibbons portray, respectively, news hosts Casey Wong and Jess Perkins, and television show host Bixby Snyder is played by S. D. Nemeth. Angie Bollings and Jason Levine appear as Murphy's wife and son respectively. Kevin Page portrays OCP junior executive Mr. Kinney who is shot to death by ED-209. The cast also includes Michael Gregory as Lt. Hedgecock and Lee de Broux as Sal.
RoboCop director Paul Verhoeven cameos as a dancing nightclub patron, producer Jon Davison provides the voice of ED-209, and director John Landis cameos in an in-film advert. Smith's partner Joan Pirkle appears as Dick Jones' secretary