Functional groups were introduced on low density polyethylene (LDPE) surfaces by treating the polymer films in air atmosphere with corona discharge through a knife-type electrode. Functional groups on LDPE surface were characterized by the measurement of water contact angle, Fourier transform infrared spectroscopy in the attenuated total reflectance mode (FTIR-ATR), and electron spectroscopy for chemical analysis (ESCA). Dyeability of corona-treated LDPE film was evaluated with K/S value. The introduction of functional groups on LDPE surface was confirmed by FTIR-ATR and ESCA analysis. The dyeability of the LDPE towards ionic dyes was improved by the corona discharge treatment.