Halocho #584 - Can one put a Mezuzah on the inside?

The Mezuzah belongs on the outside on the doorpost. In a wide doorframe it belongs in the Tefach (~8cm - 3 inches) closest to the outside.

The Minhag in many places is to put it up at an angle, with the top leaning inwards. If there's not enough space, it can be affixed vertically.

If there is no space on the doorframe for the Mezuzah to be placed on the outside, then it can be affixed on the inside.

If one is worried about theft, then the Mezuzah can be put on the inside.

However, it's preferable to carve a hollow in the doorpost and affix the Mezuzah into the indent, rather than putting it inside the house.

When a Mezuzah is carved into the doorpost it must still be upright; one cannot drill a horizontal hole and put the Mezuzah into it. The indent cannot be more than a Tefach deep, and it cannot be totally hidden; it must be obvious to the keen observer that there's a Mezuzah on the door.

When a Mezuzah is affixed to the inside, care must be taken that it's affixed to the doorpost (and not to the wall, nor the door) and that it's within the Tefach (~8cm - 3 inches) of the door. The top should be slanted inwards.

Source: Kitzur Shulchan Aruch 11:6, 9

- Danny
Monday, 25 Sivan 5770