The article is an attempt to provide a comprehensive review of the experimental findings on foreign vocabulary learning. Almost all the research has been carried out on learning word pairs made up of a foreign word paired with its mothertongue translation. The first section of the review compares direct and indirect vocabulary learning. The second section reviews the evidence on how much vocabulary can be learned in a given time, how many repetitions are required for learning to occur, and why some words are more difficult to learn than others.