Unlike externally-bonded fibre reinforced polymer (EB-FRP) strengthening system, mechanically-anchored unbonded FRP (MA-UFRP) strengthening system does not require surface preparation, adhesive application, or skilled labours. The potential of using MA-UFRP system to enhance the structural performance of one way reinforced concrete slabs is investigated in this paper. A total of six slabs, each of 500 × 100 × 1800 mm, reinforced with three No. 10 deformed steel bars, were constructed and tested to failure under four-point bending. One slab was used as control while the other five slabs were strengthened with various FRP strengthening systems. Two slabs were strengthened with EB-FRP strips, one slab with end-anchorage and one slab without end-anchorage. The remaining three slabs were strengthened with MA-UFRP strips having various anchorage locations. Test results indicated that MAUFRP strengthening system was effective in increasing the slab strength. However, the strength gain was less than that obtained by the use of EB-FRP strengthening system.