Yes, dogs can eat sardines in tomato sauce. Apart from the fact that sardines in tomato sauce can make an excellent source of protein for your dog, it also has a good taste and can be easily digested by your hound.
However, some experts believe that even though sardine may not contain any toxic ingredient, there is a high possibility that it might contain some bad substances that could be harmful to your dog. Therefore, it is advisable that you give to your dog moderately and also, make sure to take advice from your vet before feeding it to your dog.