Genetic variation in glutamatergic signalling pathways is believed to play a substantial role in the aetiology of schizophrenia. The N-methyl-D-aspartate receptor subunit gene GRIN1 has been proposed as a candidate gene for schizophrenia. We tested for a potential association between schizophrenia and four single nucleotide polymorphisms (rs4880213, rs11146020, rs6293, and rs10747050) and one microsatellite marker at GRIN1 in a German sample of 354 patients and 323 controls. We found significant associations in single-marker and haplotype-based analyses (P<0.05). Significance was more pronounced (P<0.01) in the subset of patients with a lifetime history of major depression, a subgroup of schizophrenia described previously as a promising phenotypic subtype in genetic studies of schizophrenia. Although significances did not withstand correction for multiple testing, the results of our exploratory analysis warrant further studies on GRIN1 and schizophrenia.