517 U.S. 308 (1996)
James O'Connor was employed by respondent Consolidated Coin Caterers Corporation from 1978 until August 10, 1990, when, at age 56, the company fired him.1 O'Connor claimed that Consolidated Coin had dismissed him because of his age in violation of the Age Discrimination in Employment Act of 1967.2 He brought suit in the United States District Court for the Western District of North Carolina.3
After the parties completed discovery, the District Court granted the company's motion for summary judgment in 1993.4 O'Connor appealed the adverse judgment to the Court of Appeals for the Fourth Circuit.5
The Fourth Circuit concluded that O'Connor's replacement was 40 years old and therefore that he had not made out the last element of the prima facie case under McDonnell Douglas.6 Finding that O'Connor's claim could not survive summary judgment without the McDonnell Douglas presumption, the Court of Appeals affirmed the judgment of dismissal in 1995.7 O'Connor then petitioned the Supreme Court for certiorari, which the Court granted in 1995 to review the Fourth Circuit's decision on the requirements for a prima facie case under the ADEA.8
Whether a plaintiff, alleging that he was discharged in violation of the ADEA, must show that he was replaced by someone outside the age group protected by the ADEA to make out a prima facie case under the McDonnell Douglas framework?9
The fact that an ADEA plaintiff was replaced by someone outside the protected class is not a proper element of the McDonnell Douglas prima facie case.10
No. The Fourth Circuit required O'Connor to prove that his replacement was outside the protected class, but since his replacement was 40 years old, it held he failed to make out the prima facie case.11 Under the proper rule, the inquiry whether the replacement was substantially younger than the plaintiff creates an inference of age discrimination.12 Here, the 40-year-old replacement of the 56-year-old O'Connor satisfies that standard, as the age difference supports an inference of discrimination based on age.13
A plaintiff alleging discharge in violation of the ADEA need not show replacement by someone outside the protected age group to establish a prima facie case under McDonnell Douglas.14