Avian influenza has become a serious concern from both veterinary and public health points of view. National and international organisations, veterinary health authorities, research institutions, diagnostic laboratories and field services make enormous efforts worldwide to detect, combat and prevent this important disease. Accordingly, the standard diagnostic protocols are being supported by a wide variety of molecular detection techniques, including improved polymerase chain reaction assays, microarray-based detection and characterisation methods, very rapid sequencing, simple pen-side tests and other on-site approaches. These recently developed 'closer to the field' methods allow rapid detection of influenza viruses and the identification of pathogenicity variants. However, in order to harmonise the diagnosis worldwide, attention has to be paid to the validation and standardisation of these technologies, to avoid erroneous interpretation of assay results, and, consequently, inappropriate epidemiological measures. This review gives an overview of the current and potential future developments related to avian influenza diagnostics.