Seth Rogen as Ben Stone

Katherine Heigl as Alison Scott

Paul Rudd as Pete

Leslie Mann as Debbie

Jason Segel as Jason

Jay Baruchel as Jay

Jonah Hill as Jonah

Martin Starr as Martin

Charlyne Yi as Jodi

Iris Apatow as Charlotte

Maude Apatow as Sadie

Joanna Kerns as Alison's Mom

Harold Ramis as Ben's Dad

Alan Tudyk as Jack

Kristen Wiig as Jill

Bill Hader as Brent

Ken Jeong as Dr. Kuni

Craig Robinson as Club Doorman

Tim Bagley as Dr. Pellagrino

Loudon Wainwright III as Dr. Howard

Stephanie Mnookin as Dr. Howard's Nurse

Adam Scott as Samuel

J.P. Manoux as Dr. Angelo

Mo Collins as Female Doctor

B.J. Novak as Young Doctor

Tami Sagher as Wardrobe Lady

Brianna Brown as Alison's Friend

Catherine Reitman as Alison's Friend

Nick Thune as Alison's Friend

Paul Feig as Fantasy Baseball Guy

Ben Meyerson as Fantasy Baseball Guy

Wayne Federman as Fantasy Baseball Guy

Melinda Bennett as Dr. Pellagrino's Nurse

Matthew McKane as Club Bartender

Steven Brill as Ben's Boss

Ana Mercedes as Maria

Nadine Griffith as Maternity Nurse at Desk

Diane Schaller as Delivery Nurse

Emersen Riley as Jonah's Girlfriend

Stormy Daniels as Lap Dancer

Nautica Thorn as Lap Dancer

Mary Brill as Real Estate Agent

Lolita Mastrolia as Daughter in Waiting Room

Joseph T. Mastrolia as Father in Waiting Room

Tracy Hartley as Lamaze Instructor

Jeffrey L. Wilson as Record Store Customer

Jessica Alba as Self (uncredited)

Steve Carell as Self (uncredited)

Andy Dick as Self (uncredited)

James Franco as Self (uncredited)

Eva Mendes as Self (uncredited)

Ryan Seacrest as Self (uncredited)

Dax Shepard as Self (uncredited)

Michelle Woods as Waitress (uncredited)