The five are among the buildings local advocates has been pushing to landmark ahead of a proposed rezoning of the area.
Of the 16 people who provided testimony at the hearing, including representatives for the owners of four of the five properties, not one person spoke against designation.
Locals and preservationists have been advocating for landmarking the buildings for years.
Each building represents the "best architectural examples of their type in the area," said LPC Chair Sarah Carroll.
Some longtime Gowanus residents oppose skyscrapers in the area and questioned why building heights have doubled from 14 to 30 stories in the proposed rezoning.
Local activists decided to stage their own public meeting when they were not getting any answers to their questions Wednesday night.
The rezoning from industrial to residential is expected to allow 30-story apartment buildings around the canal and be a bonanza for current owners of industrial property in the area.
The long-awaited Draft Planning and Land Use Framework of Gowanus has just been released by the Department of City Planning.