ABSTRACT: The genotype of the hepatitis C virus (HCV) is essential for determining treatment duration in clinical practice and for epidemiological and clinical studies. Currently, few genotyping assays that determine the HCV subtype are available. This report describes a microarray-based molecular technique for identifying the HCV genotype and subtype. It uses low-density hydrogel-based biochips containing genotype- and subtype-specific oligonucleotides based on the sequences of the NS5B region of the HCV genome. The biochip contains 120 oligonucleotides that identify genotypes 1 to 6 and 36 (1a, 1b, 1c, 1d, 1e, 2a, 2b, 2c, 2d, 2i, 2j, 2k, 2l, 2m, 3a, 3b, 3k, 4a, 4c, 4d, 4f, 4h, 4i, 4k, 4n, 4o, 4p, 4r, 4t, 5a, 6a, 6b, 6d, 6g, 6h, and 6k) subtypes. The procedure included amplification of a 380-nucleo