Following the completion of the Main Building in 1864 planning was initiated for a chemical laboratory for the Institute. Construction was started in 1865 and work on the brick structure was completed the following year. The cost of the building was $10,000, half of which was donated by Rensselaer President John Flack Winslow. In recognition of his leadership and generosity, the new laboratory was named after Winslow. The state of the art facility was designed and equipped under the direction of Professor of Chemistry Henry B. Nason who had received his Ph.D. at the University of Göttigen.
The laboratory, situated immediately north of the Main Building, was originally sixty feet long by forty feet wide and three stories high. Following a fire in 1884, which destroyed the upper story, the building was enlarged. After a second fire in 1902 a south wing was added bringing its total length to ninety feet. A third fire damaged the building in 1904. Winslow continued to be used as a chemical laboratory until 1907 when it was converted into a shop for the use of students in the new mechanical and electrical engineering degree programs. A foundry and forge and pattern and machine shops were installed to meet the needs of the students. The building was enlarged to its present one hundred by forty-two feet in 1930-31 and new electrically powered equipment installed. In 1990 the Winslow Building was added to the National Register of Historic Places.