The lens wet weight (LWW) and its relationship with fetal age was determined for 32 lenses between gestational ages of 119 and 242 days. In addition to the water content, lens dry weight, water-soluble (WS) and water-insoluble (WI) protein content were determined. The increase in LWW with increasing fetal age appeared to be exponential. The WS protein content increased from 2.9 to 15.3 mg and that of the WI from 0.07 to 0.53 mg. The lens water decreased from 82.2 to 75.7%. This decrease reflects the protein increase during gestation. A formula expressing the relation between LWW and fetal age was calculated and compared with formulae calculated from results obtained by other authors.