A Moloney Murine Leukemia Virus (MMLV) Reverse Transcriptase (RT), which exhibits high sensitivity and efficiency, and RNase Inhibitor (Ribonuclease Inhibitor) which inhibits a broad spectrum of eukaryotic RNases, including RNases A, B and C. RNase-Tolerant MMLV-RT shows no inhibition of polymerase or reverse transcriptase activity, so can be used in cDNA synthesis or one-step RT-qPCR reactions. RNase-Tolerant MMLV-RT is useful in any applications where the presence of RNases is a potential problem.