Specific alterations in the genetic material of RNA viruses rely on a technique known as reverse genetics. Transfection of cells with the altered generic material is a critical step of this procedure. In this report we have compared RNA and cDNA transfection methods for the efficiency of transient protein expression and rescue of (recombinant) infectious bursal disease virus (IBDV). Quantitative expression analysis of the secreted alkaline phosphatase reporter protein, and qualitative expression levels of an IBDV protein showed both that cDNA transfection results in a much higher level of protein expression than RNA transfection. Because the rescue of a crippled variant of IBDV was achieved consistently using the cDNA transfection method, but failed when we used the RNA transfection method, we favor the cDNA transfection method for the rescue of (recombinant) IBDV from cloned cDNA.