The fire started around 2:30 Friday morning in a home on the 300-block of Washington Avenue in Phoenixville.
Firefighters arrived to find flames and smoke pouring out of the three-story twin.
When crews were told a man was trapped on the third floor, they fought through the flames to rescue him. There's no word on his condition.
About 25 minutes after the fire broke out, a second alarm was struck and five fire companies, including at least one from Montgomery County, moved in to help.
It took about 45-minutes to place the fire under control.
The Pennsylvania State Police fire marshall is looking for the cause.