A new sensitive and selective PVC-based membrane sensor for Al(III) ion was constructed by employing Zinc(II) complex of Thiophenealdehydethiosemicarbazone [Zn(LL2)2]Cl2 as ionophore material. The best performance was recorded with a membrane having a composition of PVC: DBP: Ionophore: NaTPB as 30: 63: 2.8: 4.2 (w/w %). The sensor shows a Nerstian response for Al(III) ion over a wide concentration range of 1.0 × 10-7 to 1.0 × 10-1 M with the slope of 19.8 ± 0.1 mV/per decade. The detection limit found was 6.7 × 10-9 M. It has relatively fast response time of ˂10 s and can be used for 3 mon without any considerable changes in potentials. The proposed sensor provides relatively good selectivity and high sensitivity for Al(III) over other mono, di and trivalent cations and could be used in a pH range of 2.4-9.5. It was used successfully as an indicator electrode in potentiometer determination of Al3+ with EDTA.