This study was carried out during 2010 and 2011 seasons on 14 years old Washington navel orange trees ( C . sinensis L .) grown on two citrus rootstocks ( Volkamer lemon and Sour orange ) and spaced at 5x5 m in private orchard at Kafrelshikh Governorate , to study the effect of the climatic conditions and fruit position on fruit splitting under Kafrelshikh Climatic  conditions . The obtained results showed that, the incidence of splitting starts lightly in September coincidence with maximum air temperature and relative humidity before and after this period followed by gradual increase of fruit maturity. Trees on both Volkamer lemon and Sour orange rootstocks gave a high percentage of splitting, reaching a maximum values in November and December. The highest percentage of fruit splitting was counted in the southern aspect and lower part than in upper part of tree canopy. Trees on Sour orange rootstock in both seasons recorded the highest percentage of splitting compared to those on Volkamer lemon.