Research into the chemical composition of saffron, the dried stigmas of Crocus sativus, has seen a renaissance in recent years. Different HPLC protocols for the analysis of saffron constituents have been established, enabling rapid authenticity control of the spice. Saffron flavor has attracted the interest of several research groups. Among the estimated 150 volatile compounds of saffron, approximately 40–50 constituents have so far been identified. Sensory studies allowed the detection of novel key flavor compounds. For some volatiles, generation from acid-labile progenitors was shown. Most recently, a considerable number of non-volatile aroma precursors could be isolated and structurally characterized. This paper reviews the present knowledge about the chemical composition of the world's most expensive spice and gives special emphasis to recent findings on saffron aroma formation.