An array-based method for performing SNP analysis is provided. In certain embodiments, the method may comprise: a) contacting a labeled genomic sample with an array comprising a first SNP-detecting oligonucleotide and a second SNP-detecting oligonucleotide that differ from each other by a single nucleotide, under hybridization conditions that provide binding equilibrium; and b) evaluating a SNP of said labeled genomic sample by comparing: i. binding of the labeled genomic sample to the first SNP-detecting oligonucleotide and ii. binding of the labeled genomic sample to said second SNP-detecting oligonucleotide.