The species of single tick eggs, larvae and nymphs was determined by PCR amplification and characterization of the hypervariable, second transcribed spacer (ITS2) of the multicopy ribosomal RNA gene (rDNA). Engorgement of larvae and nymphs did not preclude species identification. The method is generally applicable for ixodid and argasid ticks and can be used for epidemiological studies requiring the identification of individuals from pre-adult stages.