WBRC-TV reports that safety equipment slowed the descent of the worker on Thursday. Authorities say he landed in mulch at the base of the building, which is under construction at Children's of Alabama in Birmingham.
The worker was outside the building's 13th floor and preparing to clean the windows when he fell.
Children's of Alabama spokeswoman Rachel Olis says the 14-story building has been under construction but is nearing completion and is scheduled to open this summer.
The worker was recovering at a Birmingham hospital. Details on his condition were not immediately available.
Doug Ecker of Hoar Construction says the worker is a subcontractor of an Atlanta construction firm.