Indole compounds, obtained from cruciferous vegetables, have been investigated for their putative anti-cancer properties. Studies with indole-3-carbinol (I3C) and its dimeric product, 3, 3' diindolylmethane (DIM), have indicated efficacy of these compounds against a number of human cancers. Available as well as emerging data suggests that these compounds act on a number of cellular signaling pathways leading to their observed biological effects. Such pleiotropic effects of these compounds are also considered crucial for their chemosensitization activity wherein they help reduce the toxicity and resistance against conventional chemotherapeutic drugs. These observations have major clinical implications especially in chemotherapy. Through this review, we have attempted to update current understanding on the state of anti-cancer research involving indole compounds. We have also summarized the available literature on modulatory effects of indoles on molecular targets such as survivin, uPA/uPAR and signaling pathways such as the NF-kappaB pathway, which are important for the apoptosis-inducing and chemosensitizing properties of these compounds.