There doesn't seem to be strict instructions about whether or not to staple your forms together. References are made to "attaching" forms to your return. To ensure they don't get separated upon initial receipt, I suggest stapling the full-page forms together with only one staple in the extreme upper left hand corner. They definitely do NOT allow two-sided printing when you print out your own forms. A video released by the IRS a couple of years ago showed IRS workers taking the first step of ripping open your envelope and using a staple remover to unstaple the forms. However, the IRS definitely says to include a check but NOT to "attach" it.
