Roll with it: The quantitative analysis of specific miRNAs from biological samples is very likely to revolutionize diagnostics of human disease. A novel method for miRNA analysis employing rolling-circle amplification (RCA) can homogeneously detect miRNA, even at concentrations as low as 10 fM. The use of T4 RNA ligase 2 (T4 RnL2) at elevated temperatures enables very good discrimination of miRNAs differing by a single nucleotide.