Methods based on SNuPE (single-nucleotide primer extension) have become invaluable tools for the rapid and highly specific detection of point mutations and single-nucleotide polymorphisms in the field of human genetics. In the primer extension reaction, a DNA polymerase is used to label a specific primer hybridized to the target sequence by incorporating a single labelled ddNTP (dideoxynucleotide). This labelling provides not only information about the complementary nucleotide of interest in the opposite strand but also a semiquantitative analysis of the sequence targeted by the primer. Since several subdisciplines of microbiology increasingly require cultivation-independent molecular screening tools for elucidating differences between either strains or community structures based on sequence variations of marker genes, SNuPE offers a promising alternative to the existing tool box. The present review describes the method in detail and reports the state-of-the-art applications of this technique both in the field of nucleic acid detections in human genetics and in microbiology.