Technical Abstract: The large serine resolvase phiC31, from the broad host range Streptomyces temperate phage, catalyzes the recombination of two differing recognition sites known as attP and attB. Minimum length sites have been determined to be 39 bp for the attP and 34 bp for the attB. In this research, the phiC31 recombinase gene was placed under control of the OXS3 promoter and introduced into Arabidopsis lines harboring a chromosomally integrated attP/attB flanked target. The phiC31 recombinase site-specifically removed the attP/attB flanked genomic DNA and the excision event was detected in subsequent generations, evenin the absence of the phiC31 gene. This establishes that germinal transmission of the excision event was obtained in the absence of the recombinase gene in the genome. The successful deletion of the genomic target sequences by this recombination system in planta, illustrates how the phiC31 recombinase can be utilized in plants to remove unneeded transgenic DNA, such as selectable markers or other introduced transgenes when they are no longer desired.