Seborrheic keratosis is a benign epidermal lesion, that commony develops in the aged. It exhibits a remarkable spectrum of histologic variations. We evaluated one hundred and one cases of seborrheic keratoses according to the histologie typing by Lever and Schaurnburg-Lever. The most common histologic type was the acanthotic type(50.5%), and the next. most common one was hyperkeratotic type(33.7%). The rest of the caces were relatively uncommon, irritated type(6.9%), mixed type(4.9%), clonal type(3.9%), adenoidal type(2.0%), and melanoacanthoma(1.0%). In 2 cases, mixed type was found in a lesion. (Kor J Dermatol 1992; 30(1): 76-80)