The effects of grafting poly(ethylene oxide) (PEO) onto the surface of a microchannel on the amplification efficiency of a microfabricated device for polymerase chain reaction (PCR) were studied. The PCR device was composed of a poly(dimethylsiloxane) microchannel and a glass-heating chip. The PEO chains were grafted using neat silane or Pluronic ® F127, and the presence of PEO was confirmed by water contact angle analysis and X-ray photoelectron spectroscopy. The surface treatments with neat silane and 10% (w/v) Pluronic ® F127 resulted in an increase in the PCR amplification of a 298-bp DNA product by 2.2-fold and 3.9-fold, respectively, while 1.7-fold and 2.3-fold increases, respectively, were observed for a 1.1-kb DNA product. Both treatments could effectively enhance PCR efficiency even when DNA template concentration was decreased from 20 to 2pg/μl. Our results indicated that these simple surface treatments could therefore be used routinely to enhance the performance of similar devices.