Histamine plays an important role in the allergic inflammation. Histamin N-Methyltransferase (HNMT) catalyses the major pathway of histamine metabolism in the human lung. A common functional single nucleotide polymorphism (SNP) within the HNMT gene (C314T) was recently related to asthma. We tested this SNP for associations with asthma and asthma associated traits in two German pediatric populations (1. MAS-cohort, n=888, 85 children with asthma; 2. asthmatic children from Freiburg, n=176). Non-asthmatic (n=515) and non-atopic (n=211) children from the MAS-cohort were used as controls. For genotyping melting curve analyses (Light Cycler System) were applied. In contrast to a previous study, no association of the HNMT 314T allele with asthma, bronchial hyperresponsiveness (BHR) or other asthma related phenotypes could be observed in either study population. We conclude that this SNP might not play a major role in the pathogenesis of asthma or BHR in German children.