Summary The endogenous levels of both cis and trans isomers of free and bound ABA, were studied in dormant and after-ripened embryos of Pyrus malus L. cv. Golden delicious. Wheat cole-optile straight-growth test and gas-liquid chromatography (GLC) were used as quantitative methods. The level of free ABA was very high in dormant embryos, mainly in cotyledons, but turned very low after three months of stratification. Bound ABA increased considerably and became dominant in after-ripened embryos. Bound trans-ABA was found only in cotyledons of after-ripened embryos. The relation between free and bound ABA levels of apple embryos and their capacity to germinate is discussed.