Ochlerotatus japonicus (Theobald) collected in gravid traps were held individually in modified BioQuip breeders in a darkened room under ambient conditions and readily oviposited on Styrofoam blocks. Counts were made of eggs laid on Styrofoam blocks, container sides, and water surface, and dissections allowed for counts of retained eggs to determine the fecundity of this species. In total, 32,970 eggs were oviposited by 289 females with a range of 3–249 eggs per female. The mean ± SD number of eggs oviposited per female, 114.08 ± 51.08, was significantly less than the mean number of eggs produced per female, 125.85 ± 47.89. Wing lengths ranged from 2.8 to 4.7 mm with a mean of 3.81 ± 0.38 mm. Wing length was positively correlated with total eggs formed (r² = 0.3481); wing = 3.22054 0.0047 total eggs formed. There was no monthly size difference although females collected during October produced significantly fewer eggs than females collected from June to September. A low egg viability of 40% was attributed to improper storage of the Styrofoam blocks on which eggs were oviposited.