Abstract: A hollow cored concrete slab is the product of the method which includes casting a base layer of concrete into a suitable form. Placing precast concrete channel members in transversely spaced relation on the freshly cast base layer with the flanges of the members in contact with the base layer and the webs of the members in spaced relation from the base layer. Casting an upper layer of concrete onto the fresh base layer and around the channel members and striking the upper layer in spaced relation above the channel members so that the upper layer of concrete covers the webs of the channel members to a given depth. The slab is then cured with the channel members remaining a structural part thereof and providing for the transversely spaced hollow cores therein.