Blot up as much urine as possible with paper towels or a clean cloth
Remove bedding and wash it separately
Mix equal parts white vinegar and water in a spray bottle
Lightly spray the stained area
Blot again with a clean cloth
Sprinkle baking soda over the damp area
Let it sit until fully dry
Vacuum up the baking soda
If odor remains, repeat the process
For stubborn stains, use an enzyme cleaner made for urine
Let the mattress air dry completely before putting bedding back on
Use a mattress protector to prevent future stains