The ability of DNA vaccines to stimulate Th1 type reactions has rendered them a promising tool for immunotherapy of type I allergy. In this chapter, we describe strategies for up-to-date anti-allergic DNA-based immunization. This includes codon optimization of allergen genes, CpG-enrichment of plasmid vectors for enhanced Th1-bias, and the creation of hypoallergenic DNA vaccines either by gene fragmentation or by forced ubiquitination, both reducing the risk of side effects. Also, detailed protocols for plasmid DNA purification, intradermal immunization, and subcutaneous allergen sensitization are provided. Read-out systems presented in this chapter are focused on humoral immune responses and comprise measurement of mediator release from basophils induced by functional IgE and an ELIS A protocol based on chemiluminescence technology.