Pistillate flower abortion (PFA) in walnuts is defined as the drop of female flowers with or without pedicles within 10-15 days after flowering. This situation is commonly observed in some walnut cultivars causes dramatic yield losses. 'Sebin' is a popular walnut cultivar among farmers in Turkey due to the quality of its fruit, yield and ease of marketability. However, in some orchards, established with this cultivar, has a fruitlessness problem. In the present study, the effects of Aminoethoxyvinylglycine (AVG, the commercial brand name is ReTain) (0, 62.5 and 125 ppm doses) and AVG plus GA(3) (45, 135 and 270 ppm doses) treatments to prevent abortion in cv. 'Sebin' were investigated. The experiments were conducted in two different ecologies. The treatments were carried out just before the receptivity period of female flowers of cv. 'Sebin'. The results showed that, the female flower abortion ratio of 'Sebin' walnut cultivar were 87.78% in Tokat ecology and 77.78% in Niksar ecology. The fruit set ratio by 125 ppm AVG treatment was determined to be 60.89% for Niksar and 57.56% for Tokat ecological conditions. The highest fruit set was obtained from 125 ppm AVG combined 270 ppm GA(3) treatment and this ratio was determined to be 93.89% for Niksar ecological conditions whereas it was determined to be 83.33% for Tokat ecological conditions. As a result, it was found that AVG alone or in combination with GA(3) is effective treatments in reducing female flower abortion for 'Sebin' walnut cultivar.