15 Musim
331 Episod
ER - Season 4
- Tahun: 2009
- Negara: United States of America
- Genre: Drama
- Studio: NBC
- Kata kunci: chicago, illinois, hospital, doctor, surgical operation, emergency room, medical drama
- Pengarah: Michael Crichton
- Pelakon: Maura Tierney, Parminder Nagra, Linda Cardellini, Scott Grimes, David Lyons, Angela Bassett