Is there a limit...

Is there a limit to the amount of text a variable can hold? I have a situation where I'm querying a SQL database for a Salesmans Biography and then echoing the variable using the syntax "$row['bio]" and for some reason the bios appear to be truncated on the larger bios. I am not processing the bios in any way shape or form so they should be complete. If in fact there is a limit, how could I formulate a work around for this problem? Thanks, Ron