Immunization to the model antigen ovalbumin was investigated using a novel intracutaneous delivery system consisting of antigen-coated microneedle arrays. The influence of the following parameters on the resulting immune responses was investigated: depth of vaccine delivery, dose of vaccine delivered, density of microneedles on the array, and area of application. The immune response was found to be dose dependent, and mostly independent of depth of delivery, density of microneedles, or area of application. Our studies show that the shortest, most tolerable microneedle arrays can be used for achieving consistent and high antibody titers. Overall, the microneedle array proves to be a very versatile delivery technology, allowing easy and reproducible antigen delivery to skin for efficient vaccination without the use of a needle and syringe.