Should I be worried if my cat didn't go to the washroom for 3 days?

Try this first. Buy a can of pure pumpkin (not pumpkin pie filling) and mix about a teaspoon in with his regular food. Do this for every meal until its normal again. If its not normal in a day or 2 i'd take him to the vet. Pumpkin is full of fibre, this will get his bowels moving normall again. It works for constipation (to get things moving) and diarrhea (so harden things up) Its basically the miracle answer for poop issues. Have you checked around your house to make sure he isn't going to the bathroom in another place? He may have a few turds hiding away somewhere.

Hope this helps

get him to the vet first... if the vet says he's ok then think about this....

if he's eating n playing with NO signs at all of sickness... im sorry to say but he must have found a new place around the house to poop!! try searching around ur house (under the bed, cupboards, cabnets, stores, or any nook n cranny) for any wierd smells. if u dont find anything, there's a possibility he may have found a place outside the house for his private business... keep a close watch on him when he goes out..

I know D A M N E D well where I would be if I hadn't gone toiddy for three days - I'd be down at the doctor's office or the emergency ward.

Here's your sign.

If it were my cat I would've called the vet two days ago. I suggest you do that very soon. Your cat may have a blockage and need immediate vet attention.