Allows genotype calling for the Illumina Infinium single nucleotide polymorphism (SNP) genotyping array. GenoSNP can call genotypes within-sample. The within-sample genotyping capability is advantageous for SNPs with very small minor allele frequencies where the existence of heterozygotes and minor allele homozygotes occur rarely. The software call probabilities are shown to be well calibrated enabling their use in downstream analyses such as phasing and genotype imputation. It could also make use of the information provided by samples ran simultaneously on the same array.