HOXA1, a member of the HOX gene family, has been implicated in tumor progression. However, the role of HOXA1 in prostate cancer is not well-established. In the present study, we found that HOXA1 was highly expressed in prostate cancer cells. We then repressed the expression of HOXA1 by short hairpin RNA (shRNA) to investigate the function of HOXA1 in prostate cancer cells. Our in vitro data showed that knockdown of HOXA1 attenuated the growth, invasion and migration of prostate cancer DU-145 and PC-3 cells. Furthermore, knockdown of HOXA1 resulted in an increased E-cadherin level and decreased Snail and MMP-3 levels in the DU-145 cells. In addition, knockdown of HOXA1 inhibited activation of ERK1/2 and AKT in the DU-145 cells. Our in vivo data revealed that knockdown of HOXA1 suppressed the growth and metastasis of prostate cancer cells. Collectively, our findings suggest that HOXA1 is involved in the regulation of prostate cancer progression, including cell growth, migration, invasion and metastasis. Thus, downregulation of HOXA1 may be a novel approach for the treatment of prostate cancer.