An RNA amplification method is particularly useful for diagnosing bacterial or viral infections or genetic disorders and for cell typing. The method includes the steps of denaturing a solution containing RNA, synthesizing a first cDNA strand from a suitable primer in the presence of reverse transcriptase, denaturing the heteroduplex formed, synthesizing a second cDNA strand from a second primer in the presence of DNA polymerase and then subjecting the cDNA formed to a sufficient number of amplification cycles. All the reactants and solvents are first placed in the same container to provide a single manipulation step that avoids the risk of contamination.