The fetal development of the trabecular meshwork of the human eye was quantitatively studied by light and electron microscopy. From the 20th fetal week onward, the progressive thickening of the trabecular meshwork was achieved mainly by the widening of intertrabecular spaces, whereas the thickness and the number of trabeculae were almost constant. Significant alterations in the number of trabecular meshwork cells did not occur with development. However, a decrease in trabecular meshwork cellularity occurred by the widening of intertrabecular spaces. As development proceeded, there was an increase in the proportion of the width of the posterior trabecular meshwork, which is the main site of aqueous drainage, in accordance with the increase of aqueous production.