A concrete slab system with self supported insulation and method of making same which comprises a poured-in-place concrete slab with an insulation board held by metal or plastic C channels. The insulation is held in place on both sides by C channels. The C channels are in turn embedded into the concrete slab and as a result, the insulation is attached to the slab itself. The embedded C channels serve not only to support the insulation board but also as concrete form-work, therefore, allowing a variety of ceiling options on the under-side of the panels, while providing support for the reinforcing steel on the upper side of said panels. This system may be used for either an inclined or flat slab design, roofs or intermediate floor applications.