Hi, is it unprofessional to deliver a 2 tier birthday cake ( 5 year old birthday) in a clean, brown corrugated box?

Not unprofessional at all. There are no special magical 'professional' cake delivery boxes. Any clean box will do.

Ok, I just wanted to make sure that it doesnt *need* to be in a white bakery box.

In many cases, if a cake is going to get messed up it's the box that will do it (or misuse of the box by the customer). If you decide that a box is necessary, Bakery Craft delivery system boxes are awesome.

http://bakerycrafts.com/Home/Items/tabid/69/SrchStr/del%20sys/Default.aspx
(scroll to the bottom of the page).

not at all. I do it every week. I buy brand new ones at WalMart every week!

I order samples from BRP Boxshop...as a hobby baker I can't justify ordering 50 or 100 but for $10 I can get 5 boxes of various sizes or cake boards..
Just an idea. I like having a box though.

I get priority mail boxes from the post office for my smaller cakes. They come in several different sizes. No one has really cared what kind of box their cake came in...they just care about the cake!

I use and re-use brown cardboard boxes for my extra-large or oddly sized bigger cakes. I used to line the box with white butcher's paper, but don't even bother with that anymore

Another 'trick' I do for 12 inch or smaller two-tier cakes is to buy extra deep pizza-like boxes with a swing lid, put the cake in and then and staple them half-open, then I use a clear cellophane to cover the gap. These boxes are cheaper for me to buy than the all white bakery boxes (although I have too many of those too!)

I never box tiered cakes, but I always provide the customer with a bakery box or two, just in case there is any left over cake. I have never had anyone complain.

Thanks! I ended up using a plain brown box, and it looked fine. Thanks for your help!