An overview is given of non-destructive techniques for measuring quality attributes of horticultural produce. First, vibration based techniques to measure mechanical properties of fruit will be reviewed. The relationship between destructive and non-destructive measures of firmness will be addressed, as well as how this relationship is affected by factors such as species, cultivar and water status of the fruit. Also the limitations of the so-called firmness index when applied to non-spherical fruit will be investigated. Next, optical techniques to measure quality attributes such as soluble solids content and firmness of fruit and vegetables will be considered. Special emphasis will be paid to inappropriate use of multivariate statistical techniques, and cultivar and orchard effects. Novel techniques such as time and space resolved spectroscopy for the estimation of light absorption and scattering properties of vegetable tissue, as well as NIR hyperspectral imaging techniques will be discussed.