‘Nadja’ tomato (Lycopersicon esculentum Mill.) set both seedless and seeded fruits under the fluctuating temperatures prevailing during late-March and early-April in Assiut district, Egypt. Entirely seedless fruits developed under the low temperatures prevailing during Dec. Seedless fruits seemed to develop vegetatively , i.e. with no need for stimulus pollination. All seedless fruits were normally jelled and appeared similar in shape and size to the seeded fruits. Study of F₁, F₂, and backcross generations for the crosses ‘Cal Ace’ × ‘Nadja’ and ‘Peto-86’ × ‘Nadja’ suggested that the expression of the trait was due to single homozygous recessive gene. Yield produced by ‘Nadja’ was higher than the F₁, F₂, and backcross generations in both the early- summer and the late-winter plantings. Potentially useful parthenocarpic segregates were found in F₂ of the two crosses for increased fruit weight of normally shaped and jelled fruits.