I have a male Chihuahua who's 5 years old and not neutered. We obviously take him for walks but he still keeps peeing all over our place. We never managed to house-train him properly but he never shows any signs as to when he needs to go. He will even do it right in front of us!
We'd appreciate any help!
If he was never housebroken, you'll need to start from ground zero, and it may take a while.
Have a professional come in and steam-clean your carpets, using a urine odor neutralizer to get rid of the urine odor.
Clean up any "accidents" immediately with an enzyme cleaner.
After he eats, take him outside for a walk and don't come back until he pees. Praise him extravagantly for peeing outside. If you can take him to the same place to pee each time, even better - he'll form a habit.
Take him out for a walk at least every couple of hours, and watch him closely for signs that he needs to pee. At his age, he should have some anticipatory behaviors that you can notice.
Don't punish him for peeing in the house - he won't learn anything from having his nose rubbed in a spot, except to fear you. If you catch him in the act, whisk him outside, don't yell, and again praise him extravagantly when he pees outside.
Hope this helps and keep us posted.
I'm no dog expert but I used to have the same problem with my cat.
Have you been to the vet to see if it might be a bladder problem? Maybe he has an unusually small bladder or has issues with bladder control.
 Anonymous's reply was promoted to an answer.
That's some pretty good advice, I hope it helped.
i have a 2 yr old boxer not neutered we take him out and we have a doggy door its not like he cant go out and do his business but he chooses to also go on his own sleeping cushsion thats not a good sign gets us very upset and he know what he is doing cause when we find it he heads for the doggy door right away anyone please give us some kind of headway why he does it and how we can some how stop him from doing it would be ever so greatful ...
I rescued an unneutered 2 year old husky mix with the same problem. Here is what I did, and it worked!:

- First off, I neutered him ASAP

- If I wasn't home or couldn't actively supervise him, he stayed in a crate

- I took him outside to potty immediately after he woke up, after taking him out of the crate, after he drank water, or after a session of playing

- His favorite tinkle spot in the house I thoroughly cleaned with an enzyme based pet stain cleaner

- I placed those dirt mats "prickly side" up next to the spot

- Anytime he went over there to sniff it I redirected his thoughts to performing a "sit" or "down" for a treat right there, so it became a treat spot not a pee spot

- I used a male dog diaper wrap until he could be trusted

5 months later and he is reliably housebroken!