How do I get rid of the smell of dog urine from my sofa?

Enzyme cleaner and deodorizer at the pet store. Nature's Miracle is one.

Try Nature's Miracle, available at Pet stores.

You may have to do the enzyme treatment more than once to completely get rid of the odor but the enzyme cleaners work very well to take away the odor.

Hi Nicki, you can try this recipe

1. In a bowl, mix 10 ounces of 3 percent hydrogen peroxide, 3 tablespoons of recently opened baking soda (note: not baking powder), and 2-3 drops of dish-washing detergent. ...
2. Pour into a spray bottle.
3. Pre-test the upholstery by spraying some cleaner in an inconspicuous place.
4. Allow it to dry.

Peroxide, like any other thing, may alter the color of the fabric, it is a good bleach. I use straight white vinegar in a spray bottle, but always check to make sure that it won't change the fabric color or texture. I have not had it alter anything yet and I have had to remove the horrible cat urine smell so many times that I can't remember. You have to make sure that you spray it enough to be absorbed how deep the urine may have gone, so it may take more than one try. Once the vinegar smell is gone give it the sniff test to see where you may need to reapply it. I have used the enzyme cleaners from the pet stores and it also take more than one try to get it all and is so much more expensive than a gallon of white vinegar.