Interleukin-6 (IL-6) is secreted in great quantity in prostatic tumoral glandular tissue with a significant higher rate in hormono-refractory phase. Importance of IL-6 dependent mechanism in prostate cancer progression is well argued. IL-6 seems to be implicated in androgen receptor activation in lack of steroid ligand, apoptosis decrease and increase of invasive capacity and angiogenesis via three major signaling pathways: MAPK, STAT3 and PI3K-Akt. As AR is a key factor of prostate cancer progression, IL-6 implication in this activation underlines IL-6 importance in prostate cancer. IL-6 also induces neuroendocrine differentiation. This phenomenon received a detailed attention because it would take part in pathogenicity and progression of prostate cancer. Although complementary studies seem necessary, taking into account its strong implication in prostate cancer progression, IL-6 seems to be a new potential therapeutic target of prostate cancer.