Reese Witherspoon as Dr. Elizabeth Masterson

Mark Ruffalo as David Abbott

Donal Logue as Jack Houriskey

Dina Spybey-Waters as Abby Brody

Ben Shenkman as Dr. Brett Rushton

Jon Heder as Darryl

Ivana Miličević as Katrina

Caroline Aaron as Grace

Rosalind Chao as Fran

Ron Canada as Dr. Walsh

Willie Garson as Maitre D'

Kerris Dorsey as Zoe

Alyssa Shafer as Lily

Gabrielle Made as Nurse Maria

William Caploe as Nurse Bill

Shulie Cowen as Nurse Jenny

Billy Beck as Mr. Clarke

Diego Sebastian as Bandage Guy

Cristian Cruz as Orderly Luis

Benjamin Hughes as Peroxide Rocker

Cara Vivien Rosenberg as Balloon Girl

Catherine Taber as Intern Karen

Chris Pflueger as Abby's Husband

Paul Cassell as Brett's Friend

Drew Letchworth as UFO Guy

Raymond O'Connor as Catholic Priest

Lucille Soong as Chinese Exorcist

Joel McKinnon Miller as Lead Ghostbuster

Victor Yerrid as Ghostbuster

Bobby Benjamin as Ghostbuster

Ron Hacker as Blues Guy

Kara Hamilton as Valerie

Nicole Wilder as KIm

Lorna Scott as Hippie Neighbour

Jeffrey Marcus as Uptight Neighbour

Ken Takemoto as Chinese Neighbour

Chaim Jeraffi as Dry Cleaner

Doug Krizner as Donald

Zoe Waters as Park Girl

Jacob Chambers as Kenny

Karen Harrison as Kenny's Friend

Ingrid Coree as Waitress

Lee Burns as Ivan the Bartender

Amita Balla as Receptionist

Tim Connolly as Security Guard

Tim Sitarz as Security Guard

Ken Clark as Security Guard

Tony Brubaker as Security Guard

Jimmy Ortega as Security Guard

Yeena Fisher as Seamstress (uncredited)

David Niles as Man on Bicycle (uncredited)