Cytokine gene polymorphisms affecting cytokine production may influence rejection and graft-versus-host disease following solid organ and haemopoietic stem cell (HSC) transplantation, respectively. Polymorphisms in the regulatory regions of several cytokine genes have been described; for example, tumour necrosis factor-alpha (TNF-alpha) has a G/A substitution at position -308, interleukin-2 (IL-2) has a T/G substitution at position -330 and interleukin-10 (IL-10) has substitutions at positions -1082(G/A), -819(C/T) and -592(C/A). Microsatellites associated with cytokine production have been detected in the first intron of the IFN-gamma gene and flanking the TNF-alpha gene. In this study, we have genotyped a single panel of healthy Northern European Caucasoids living in the south-east of England for the above-mentioned polymorphisms and compared the results to those published for other populations. A PCR method using sequence-specific primers (SSP) was developed for genotyping the IL-2 polymorphism, and the ABI PRISMtrade mark 310 genetic analyser was used to detect the TNF-alpha and IFN-gamma microsatellites. The allele frequencies of all the studied polymorphisms were consistent with those reported for other UK Caucasoid populations, but differences were observed when compared to other Oriental, African and Caucasoid groups. If these cytokine polymorphisms prove to have functional consequences, then any differences across population groups may have significant clinical relevance in disease and in the outcome of solid organ and HSC transplantation.