An electrophotographic toner contains at least a binder resin and a colorant, and log.sub.10{[Cu]/[C]} satisfies the following equation (1): -5.0.ltoreq.log.sub.10{[Cu]/[C]}.ltoreq.-3.5 (1) in which, [C] represents a carbon content (%) and [Cu] represents a copper content (%), measured with fluorescent X-ray. An electrophotographic developer containing the toner, a method for producing the toner, and a method for forming an image by using the toner are also provided.