Bilateral pleural effusions usually have a single causative factor, such as heart failure or malignancy. Contarini's syndrome refers to the occurrence of bilateral pleural fluid accumulation which can be explained by a different cause for each side. Literature search finds, along with 5 new descriptions from our center, totaled 12 cases. A frequent combination is that of a parapneumonic effusion that triggers heart failure, which in turn produces a contralateral transudate. Journal of Hospital Medicine 2012;. © 2011 Society of Hospital Medicine