Summary Fruit development was observed in apple cvs. 'Elstar' and 'Jonagold' by recording the relative fruit growth, respiration, fruit firmness and starch degradation. Results were obtained by measurements on 60 fruits every week over a period of 4 months. Additionally spectral reflectance in the visible range was recorded non-destructively on fruit skin and associated tissue in order to determine the chlorophyll content decrease during fruit ripening. Maturity determination was improved by using spectral reflectance data. Prediction of fruit development stage was further enhanced by separating the analysis for unripe and ripe fruits.