Although many casting directors and producers may prefer the term open call audition, many struggling actors and singers know the meaning of a cattle call all too well. A cattle call audition is a process in which hundreds or even thousands of performers are allowed to vie for a certain number of roles. If a cattle call or open audition for the musical Grease were being held, for example, the theater would be filled to capacity with hundreds of aspiring actors wearing black leather jackets and ducktail hairstyles. Each candidate in a cattle call may get to perform one line from a song or recite a few lines of dialogue.

The idea of a cattle call or open audition is said to have come from the earliest days of the Actors' Equity Association (AEA), a powerful theatrical union. Many theatrical and movie roles were being offered exclusively to established actors, not the rank and file members of the AEA. The cattle call, or open audition, became a requirement for almost all union productions, although the auditioning actors were still obligated to join the AEA before receiving notice of these cattle calls.

For many modern actors, the cattle call audition process has become a way of life. Notices of open cattle call auditions are usually posted in trade magazines or given to recognized talent agencies. An actor may discover a suitable cattle call announcement, or his or her agent may pass on the information. A typical cattle call announcement contains the location of the audition, a basic description of the available roles, suggestions for actors, and a time to arrive at the site.

It would be unusual for the director or producers to appear at a cattle call audition, although some may want to participate in order to find a possible diamond in the rough, an unknown candidate with significant talent. For larger productions, a casting director is usually hired to make wholesale casting decisions during a cattle call. The casting director usually understands what the artistic director is looking for in an actor, so he or she can narrow down the list of candidates to be seen again later. A cattle call audition generally ends with a dismissive "thank you" or a request for a return visit, known as a call back.

Quite often the director and producers have already decided on specific actors for each available role, but union rules specifically dictate the need for open or cattle call auditions. Sometimes the casting director will audition and summarily reject almost every candidate during a cattle call. Actors understand how competitive the entertainment business can be, so many of them view cattle call auditions through jaundiced eyes. The chances of winning a major role through a cattle call are notoriously slim, so many struggling actors concentrate more on developing industry contacts and improving their acting skills.