In this work, several polyamide thin layer membranes were prepared and modified with polyamidoamine (PAMAM) dendrimers in different generations (G(0), G(1), and G(2)) and different concentrations (0.5, 1.5 and 3 wt.%) to investigate the occurring changes in the performance and morphology of the prepared thin layers. SEM and AFM data (reinforced with SPM software) proved that the dense and compressed surfaces were fabricated by loading and increasing of the generations and concentrations of PAMAM. In addition, the MWCO of the membranes drastically decreased. The chemical properties of the surface were investigated with ATR-IR and the occurring changes were studied. The zeta potential measurements illustrated that the surface charge of the thin layers was changed with alteration in the generations and concentrations of PAMAM. Additionally, in some cases the rejection capability of NaCl increased over 90%. Furthermore, the contact angle results clearly demonstrated an enhancement in the hydrophilicity of the membranes. The flux recovery ratio of the thin layers increased from 63% (in the unmodified thin layer) to near 97% in the thin layer composed of 3 wt.% G(o). (C) 2015 Elsevier B.V. All rights reserved.