Aberrant regulation in the adhesive ability of cancer cells is closely associated with their metastatic activity. In this study, we examine the role of ErbB-2 in regulating the adhesive ability of androgen receptor (AR)-positive human prostate cancer (PCa) cells, the major cell population of PCa. Utilizing different LNCaP and MDA PCa2b cells as model systems, we found that ErbB-2 activity was correlated with PYK2 activity and adhesive ability in those cells. Increased ErbB-2 expression or activity in LNCaP C-33 cells enhanced PYK2 activation and cell adhesion, while the high PYK2 activity and the rapid adhesion of LNCaP C-81 cells were decreased by diminishing ErbB-2 expression or activity. Knockdown studies revealed the predominant role of ErbB-2 in regulating LNCaP C-81 cell adhesion. Coimmunoprecipitation showed that C-81 cells had increased interaction between ErbB-2 and PYK2. Elevated ErbB-2 activity in LNCaP cells correlated with increased ERK/MAPK activity and enhanced adhesive ability, which were abolished by the expression of K457A-PYK2 mutant or the treatment of PD98059, a MEK inhibitor. In summary, our data suggested that ErbB-2, via PYK2-ERK/MAPK, upregulates the adhesive ability of AR-positive human PCa cells.