Abstract: A study was carried out to examine the effect of bud scale removal (BSR) and aminooxy acetic acid (AOA) on bud break and 1-aminocyclopropane-1-carboxylic acid (ACC) content of 'Muscat Bailey A' grapevines using single-eye cuttings. Samples were collected monthly from October to February. Single-eye cuttings were subjected to these treatments; BSR, BSR + AOA, control and AOA. The results show that in October and November, BSR and BSR+AOA were more effective on bud break without big difference between the two treatments. Whereas, control and AOA were found to be more effective from December up to February. In October, ACC content recorded a marked increase after one week and decreased afterwards under BSR and BSR + AOA. However, it showed a continuous increase under control and a reverse trend under AOA. In November, it increased after one week and decreased in the fourth week under all treatments. A continuous increase was recorded in December under all treatments. In January, there was no significant change under control with time and AOA treatment exhibited decline with time, while BSR and BSR + AOA treatments recorded small increment and then decreased. In February, it decreased under all treatments with time. The results indicate that bud break of grapevine seems to be associated with the promotion of ethylene biosynthesis caused by wounding stress.