Small nucleolar RNAs (snoRNAs) constitute a group of non-coding RNAs principally involved in posttranscriptional modification of ubiquitously expressed ribosomal and small nuclear RNAs. However, a number of tissue-specific snoRNAs have recently been identified that apparently do not target conventional substrates and are presumed to guide processing of primary transcripts of protein-coding genes, potentially expanding the diapason of regulatory RNAs that control translation of mRNA to proteins. Here, we review biogenesis of snoRNAs and redefine their function in light of recent exciting discoveries. We also discuss the potential of recombinant snoRNAs to be used in modulation of gene expression.