Phosphatidic acid and phosphatidylserine are negatively charged abundant phospholipids with well-recognized structural roles in cellular membranes. They are also signaling lipids since their regulated formation (or appearance) can constitute an important signal for downstream responses. The list of potential effectors for these lipids is expanding rapidly and includes proteins involved in virtually all aspects of cellular regulation. Because it is not always clear whether these effectors recognize the specific phospholipids or a general negatively-charged membrane environment, questions about specificity must be addressed on a case by case basis. In this review we present an up to date list of potential phosphatidic acid- and phosphatidylserine-binding proteins.