Electromagnetic interference (EMI) shielding effectiveness (SE) of carbon nanotube (CNT) macro-films with large-area was measured. The results show EMI SE of 61–67dB has been achieved by the macro-film with only ∼4μm thick. It is much higher than other shielding materials with light weight. Morphological analysis reveals conductive interconnected CNTs and iron nano-particles lead to a high EMI SE. Considering the flexibility, thickness, and negligible weight (∼0.1gcm −3 ) of the macro-film, it exhibits an excellent competitiveness for EMI shielding materials.