"What I Am" is the fourth episode of the third season of Grey's Anatomy and the 40th produced episode of the series. It is also the 40th produced episode of the Grey's Anatomy franchise. It was broadcast on October 12, 2006.
The arrival of Mark Sloan shakes up Seattle Grace and leaves Addison questionning her abilities as a doctor when his appearance leaves her distracted. Meredith faces an emergency appendectomy and, while she is a patient at the hospital, Derek and Finn continue to compete for her affections. Izzie meets with Denny's father while Cristina learns Burke's potentially dangerous secret and takes action to save his career. Callie continues to feel pushed aside by George's commitment to his friendships.
- "At some point during surgical residency most interns get a sense of who they are as doctors and the kinds of surgerons they're going to become. If you ask them they'll tell you they're going to be general surgerons, orthopedic surgerons, neurosurgerons. Distinctions which do more than describe their area of expertise, they help define who they are because outside the operating room, not only do surgerons have no idea who they are, they're afraid to find out."
- "I know we've had our differences and I'm sorry we've been out of touch but believe it or not I was trying to make everything better. I know you're angry and I hope you'll forgive me. Turns out sometimes you have to do the wrong thing. Sometimes you have to make a big mistake to figure out how to make things right. Mistakes are painful but they're the only way to find out who you really are. I know who I am now, I know what I want. I've got the love of my life, a new heart, and I want you guys to get on the next plane out and meet my girl. Everything's going to be different now, I promise. From here on out nothings ever going to be the same. I love you. Bye."
- "If Looks Could Kill" - Camera Obscura
- "Standing In The Way Of Control (Le Tigre Remix)" - The Gossip
- "Back In Time" - Au Revoir Simone
- "So-Lo" - Kate Havnenik
- "Province" - TV On The Radio
- "Fall For Nothing" - Mindy Smith
This episodes' title references the album What I Am, originally sung by Edie Brickell & The New Bohemians