I will be honest when we first took the pieces out of the box we were about to put it back in and send it back!  There were so many pieces but after separating everything and reading the directions it went together super quick!  Make sure to read the directions or else the holes won't match up.   My cats never like anything new so it took them about two weeks to go near it but now they love it and are on it 24/7 they both have claimed out different sections for themselves.  The best cat tree ever!