The present specification relates to a composition containing a peptide having effects of increasing telomerase activity and extending a telomere, and more specifically, to a composition containing a telomerase-derived peptide, thereby being effective for preventing, alleviating and treating diseases, caused by a decrease in telomerase activity or a reduction in telomere length, and symptoms caused by cell aging or damage. According to one aspect to the present invention, the peptide increases telomerase activity and is effective for extending a telomere, and thus a method for treating diseases induced by an abnormal decrease in telomerase activity and by the length reduction or loss of a telomere and alleviating symptoms caused thereby can be provided.
