Full_Name: Shaun Morris Version: AS 522 OS: Windows NT 4.0 Submission from: (NULL) (208.248.21.128) $_ = "x"; my(@params) = /^(x)?\s*x/; print join(';', @params), "\n"; The code above prints 'x' under AS 522. Under AS Perl 5.003_07 build 306, it correctly prints nothing. If you remove the \s*, it works properly.