Modern science is actively engaged in search of optimal structures types. The prefabricated monolithic slabs combine monolithic and fabricated structure advantages. Systems of the prefabricated monolithic constructions correspond to the modern trends, but require special attention and scrutiny. There are results of prefabricated monolithic slab fire test in the article. Experimental studies have shown positive results of prefabricated monolith slab construction performance. Signs of construction limit states were not registered after 3 hour fire testing.