Aptamers are proving to be exceedingly effective in a number of applications. Given the disadvantages of antibodies, such as batch-to-batch variation and cross-reactivity, aptamers have the potential to revolutionize the field of histopathology due to their high specificity and the ease of their synthesis and modification. Here, we describe a chromogenic staining method for paraffin-embedded tissue sections with FITC-labeled aptamers.