The Arabidopsis homeotic gene AP2 is essential for floral meristem development and organ specification. In this study, we report the isolation and sequence comparison of the AP2 homologue of Brassica rapa (BAP2). The results showed that the BAP2 DNA sequence was 2138 bp in length and contained nine introns. It shared 90% identity with AP2 in the coding region. The putative BAP2 polypeptide contained a nuclear localization signal (NLS) sequence and two copies of highly conserved AP2 domain, suggesting that BAP2 may function similarly to AP2. Two nucleotide variations were detected in DNA sequences from wild-type and apetalous B. rapa plants at the BAP2 locus, while the putative polypeptides were identical. We propose that BAP2 is not likely to be responsible for the apetalous mutation in B. rapa.