This study was conducted for two successive seasons 2009 and 2010 at a private vineyard located at El-Khatatba region on 16-years-old. Roumi Ahmar grapevines. Grapevines were irrigated by the drip irrigation system, trained as double cordon on double T trellis system. Total number of buds per vine was fixed to (64 buds) (16 spurs X 4 buds each). The aim of this work to study the effect of old wood size on total yield per vine, bunch quality, bud behaviour and dynamic of wood ripening.  Old wood size was varied as to give rise to three levels: high (13-15 Dec³), medium (11-12 Dec³) and low (8-10 Dec³). The obtained results indicated that there were significant increases on bud behaviour expressed as percentage of bud burst, percentage of fruitful buds and bud fertility as old wood size was increased. Data showed that yield/vine, number of bunches per vine, bunch weight, weight of rachis, average berry weight and percentage of total soluble solids increased as size of old wood was increased. Also, wood ripening was found to increase by increases size of old wood. The weight of wood prunings was determined as Kg per vine. The values were considered as an indicator for vine vigour. This estimate was shown to increase by increasing size of old wood: While, No of berries per bunch, berry index, compactness coefficient and acidity were decreased. Bud behaviour at the different position lengthwise the spur from (1^st bud to 4^th bud) was found to increase i.e. as percentage of bud burst, percentage of fruitful buds and bud fertility were increased as old wood size was increased. From these results it can be included the importance of old wood size on yield/vine and bunch and berry quality of Roumi Ahmar grapevines.