When they arrived on the scene, firefighters found flames shooting out the first and second floor windows.
An older man was hanging out a second floor window with smoke pouring out around him. Firefighters brought the man down safely by ladder.
Then, they discovered an older woman sitting in a back stairwell.
"We got the ladder out, assisted the gentleman down, and it took a little while because he had a slight disability. But we got him down, and the paramedics treated him very well," said Vincent Wurtz, Melrose Fire Dept.
"When we had her in the back, she just, she was a little frantic. But, once again, she was pretty calm. She was really concerned about her dog," said Frank Islami, Melrose Fire Dept.
The dog was rescued.
The injuries to the victims did not appear life-threatening Sunday night.
Investigators are trying to determine the cause of the blaze.