Idiopathic eruptive macular pigmentation (IEMP) is rare skin disorder characterized by asymptomatic, grayish brown-pigmented macules involving the neck, trunk and proximal portions of the extremities. Degos et al. first described it in 1978. The disease occurs primarily during childhood and adolescence usually without a history of erythema, drug medication or any other skin disorder. The lesions usually appear abruptly and gradually disappear spontaneously over the period of a few months to years. Histopathological examination shows pigmented epidermis and many melanophages in the upper dermis along with perivascular inflammatory infiltrate.In this study, we presented 10 cases of IEMP that fulfilled the criteria of diagnosis according to de Galdeano et al. (1996) and discussed how to differentiate it from other strikingly similar disorders such as EDP, AD and LPP.Ashy dermatosis has the same clinical and histopathological picture of IEMP so they are considered as one condition.Unlike idiopathic eruptive macular pigmentation (IEMP) and ashy dermatosis (AD); lichen planus pigmentosus (LPP) and erythema dyschromicum perstans (EDP) have similar histological findings; they both show vacuolation of the basal cell layer, necrotic keratinocytes and numerous colloid bodies. In addition, they have the same immunofluorescence and electron-microscopic findings. So they are considered as one condition.It seems that no treatment is necessary for IEMP because of spontaneous resolution of the lesions and the treatment with oral retinoids is not proved yet to be effective.