AbstractFor many food products the presence of volatile aroma components is a prime quality feature. Upon drying part of these components may be lost, leading to unbalanced flavour patterns in the reconstituted product. The mechanisms of aroma loss in most drying processes are well understood by now. For homogeneously dissolved aroma components this can be described succesfully by Thijssen's selective diffusion theory. Somewhat more complicated is the loss of aroma components which are present in the form of a dispersion.An extensive overview is given of theory and experimental work on aroma loss in slab drying, spray drying and freeze drying. Practical processing rules following from the basic insights are discussed. It is the intention to present a broad coverage of the subject.