Nitric oxide synthases (NOS) and mitochondrial DNA-polymorphisms have been associated with the risk of developing Parkinson's disease (PD). In this report, we genotyped 450 PD-patients and 200 controls for three polymorphisms in the endothelial, inducible and neuronal NOS-genes, and for the T4336C and A10398G mitochondrial DNA-polymorphisms. None of the eNOS (intron 4 VNTR), iNOS (exon 22 A/G), or nNOS (exon 29T/C) were significantly associated with PD. Mitochondrial 4336C increased the PD-risk among women (OR=6.13), while the 10398G had a protective effect (OR=0.52). We did not find significantly interactions between the NOS and mitochondrial polymorphisms in the risk for PD in our population.