[Sandra Brown]

My walls are already painted and i only want to repaint. Is there any significant difference in the outcome if i use ceiling paint as a primer?

[RickJ]

Ceiling paint is just paint. If you have water stains or repairs to cover, it's best to use a primer before painting the walls.

There are good water based primers out there if you don't want to go with the stinky and messy oil based stuff.

[ballengerb1]

You do not need a primer for previously painted walls.

[Fr_Chuck]

Yes, is there a reason you want to use a primer ? Unless as noted there are stains you are wanting to cover up, you do not prime a previous painted service ( normally)

[RickJ]

You do not need a primer for previously painted walls.

If you have water stains that have bled through the old paint, or you have repairs that need dealt with, then you do indeed need to use a primer over the old painted walls.

If, though, the walls that you are re-painting have no problems that need primer, then you certainly can just paint over them without the use of a primer.

[Kena60]

Dido everything above said but clarifying here. You have left over ceiling paint and are now painting the walls? You want to use the ceiling paint on the walls as a primer so you don't have to throw the ceiling paint out? All painted surfaces are latex? If you have stains to cover or have patched any holes etc, drywall tape from repairs, these should be primed and you could use the ceiling paint but a true primer would give better results. Make sure walls have been washed down clean before priming/ painting.