The present invention provides a new procedure for the synthesis of cDNA from single cells after microdissection. It has the advantage that it is cost-efficient and can be carried out quickly with only few steps, even by less skilled laboratory employees. For the first time, the time-consuming and risky step of RNA isolation is omitted during cDNA synthesis from single cells by performing lysis and cDNA synthesis in the same reaction tube and in one buffer solution, which provides reliable and contamination-free results. The buffer is composed of NP40, carrier-RNA and Super RNAsin, as well as dNTPs and cDNA synthesis primers.