Extensive partial unilateral lentiginosis is a rare disorder characterized by multiple lentigines that are grouped within an area of normal skin, often in a segmental pattern. The distribution of lentigines is generally unilateral with a sharp demarcation at the middle. The histology shows typical features of lentigo simplex and an epidermal proliferation of a basal melanocytes, elongation of rete ridges and dermal melanophages. Differential diagnosis must be made with segmental lentiginous naevus, a zosteriform disposition of spilus naevus. We report two female patients with multiple pigmented macules located on the neck, anterior and posterior trunk, superior limb, sharp interruption at the midline, involving the left side at one patient and the right side at the other patient. The histology was characteristic for lentigo simplex. For both patients the diagnostic was extensive partial unilateral leniginosis.