| Litigants: | Slack v. McDaniel |
| Arguedate: | October 4 |
| Argueyear: | 1999 |
| Rearguedate: | March 29 |
| Reargueyear: | 2000 |
| Decidedate: | April 26 |
| Decideyear: | 2000 |
| Fullname: | Antonio Slack v. McDaniel, Warden, et al. |
| Usvol: | 529 |
| Uspage: | 473 |
| Parallelcitations: | 120 S. Ct. 1595; 146 L. Ed. 2d 542 |
| Majority: | Kennedy |
| Joinmajority: | unanimous court (part I); Rehnquist, O'Connor, Scalia, Thomas, Ginsburg (part II); Rehnquist, Stevens, O'Connor, Souter, Ginsburg, Breyer (parts III, IV) |
| Concurrence: | Stevens |
| Joinconcurrence: | Souter, Breyer |
| Concurrence/Dissent: | Scalia |
| Joinconcurrence/Dissent: | Thomas |
Slack v. McDaniel, 529 U.S. 473 (2000), was a United States Supreme Court case in which the Court held that under the Antiterrorism and Effective Death Penalty Act of 1996, a certificate of appealability must be issued by a circuit Justice of judge before an appeal can proceed. The certificate of appealability (COA) may only be issued if the applicant "has made a substantial showing of the denial of a constitutional right."[1]