Atomic Fluorescence Spectrometry (AFS) is an ideal detection technique for speciation studies concerning hydride forming elements (mainly As, Se and Sb) and Hg. The analytical features of AFS, such as detection limits below the µg L⁻¹ and the wide linear calibration range, up to the mg L⁻¹, allow its application to a great variety of environmental, biological and food samples. AFS represents a suitable alternative to other atomic spectrometers commonly employed in speciation studies such as Atomic Absorption Spectrometry (AAS) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The instrumentation used for AFS and the design of the vapour generation and optical layouts required to sustain the full benefits of the AFS approach are also described. The present review explains and comments on the instrumental couplings of chromatographic (HPLC and GC) and non-chromatographic separations (CE) with AFS detection, with online hydride generation for the speciation of inorganic and organic compounds of As, Se and Sb, and cold vapour for Hg. Other optional intermediate steps are online photo-oxidation (UV), pyrolysis or Microwave Assisted Digestion (MAD) for non-directly reducible compounds. Many different sample types (e.g. water, soils, air, biota, food) have been analysed using these instrumental couplings with AFS detection. These are summarised and discussed.