Knowledge about spatial distribution of growth is essential for basic understanding the leaf growth process. In grasses the elongation zone is located at the base of the leaf blade and is enclosed by sheaths of older leaves. In this experiment holes using a fine needle through the bases of leaf elongation zone (to 30㎜ above attachment) of perennial ryegrass (Lolium perenne L.) were made, and then the displacement of the pin holes after pinning was measured. Pinning every 2 ㎜ caused a reduction of about 50% of leaf elongation rate (LER) after 6 hr, but LER was recovered soon to about 80% of the control leaves in daily leaf elongation. The pinning method used was useful and convenient to measure spatial distribution of growth in the elongation zone of grass leaves. Growth of vigorous tillers (with rapid LER, new elongating leaf and long sheath) was terminated at about between 24 and 27 ㎜ above attachment, which may be positively related to vigorous cell division and active cell elongation. However, growth of non-vigorous tillers (with late LER, old leaf and short sheath) was terminated at lower part (less than 18㎜) from attachment. The maximum growth in vigorous tillers was seen at 7 to 13 ㎜, but that of non-vigorous one was located at 5 to 9 ㎜ above attachment in the elongation zone. High LER was increased by more than 80% in LER than low LER leaves. The length of the elongation zone in perennial ryegrass was 24 to 27 mm above the attachment in the leaf base.