The aim of this study was to explore the influence of different anticoagulants on PCR amplification, as well as to optimize PCR amplification of blood samples for successful mutation detection. For the purpose of this study the amplification of part of methylenetetrahydrofolate reductase (MTHFR) gene exon 4, in which mutation C677T is located, was performed. With the exception of sodium heparin, the presence of other commonly used anticoagulants (sodium citrate, K3EDTA, lithium heparin) made it possible to obtain satisfactory amplification. The described method, apart from saving time and material, enables successful PCR-based analysis even when a very small amount of blood sample is available.