How many Greek gods or goddesses were there in the Roman days?

zero -- just like there are now. there were like 20 or so but there were a lot of people that made up their own greek gods or godess Answer: (link appended) lists 370 Greek gods and goddesses with almost as many alternate names. The Romans were never shy about taking thins and appropriates almost the entire pantheon and slapped their own names on the deities.