Cone electroretinograms (ERGs) in response to different color flashes were examined using a Ganzfeld stimulus in 19 eyes after successful retinal detachment surgery. In the operated eyes, the short wavelength sensitive (S-) cone b-wave was reduced more than the mixed long (L-) and middle (M-) wavelength sensitive cone b-waves. The ratio of the S-cone ERG b-wave amplitude between operated eyes and fellow eyes was significantly lower than the L- and M-cone ERG b-waves (P < .01). These ERG results indicated that the S-cone system is more impaired than the L- and M-cone systems after retinal detachment surgery.