Kitten refuses to use litterbox.

Question
My husband and I have 2 wonderful kitten who get along fine. The oldest kitten is about 10 months old, he has been trained to use the litterbox since day one and continues to do so. The youngest kitten is about 4 months old, he was trained to use the litter box but will only use it SOMETIMES, all other times he will urinate any and everywhere all over the house and the smell is so strong. Neither cat has been neutered yet. We have plans to do so. We don't understand why only one cat will do this, even if neither one has been fixed yet. We don't want to take him to a shelter, but we don't want him urinating all over our house either. Please help

Mr.&Mrs.D.L.Edmonds

Answer
First of all, you must get both of the cats neutered ASAP as it is likely that this is a territorial issue and male marking behavior.  The older cat could be denying the younger cat access to the box because he is protecting "his" box and territory forcing the little one to go elsewhere.  Make sure you have THREE litter boxes and they are scooped out daily and clean.  You can also use Cat Attract Litter to try to help attract them back to the box.  Feliway/Comfort Zone can also be used to help.