Genotyping is an important tool for epidemiological and population genetic studies in protozoan parasites. The most commonly used method for genotyping is polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) analysis of single nucleotide polymorphisms (SNPs). However, PCR-RFLP analysis is labor intensive, and only a proportion of the SNPs are recognized by currently available restriction enzymes. Here, we have developed a more efficient microarray-based method to genotype SNPs in the protozoan parasite Toxoplasma gondii. This method is sensitive, accurate, and capable of analyzing multiple SNPs simultaneously in a high-throughput format.