In this study, I would like to present the French influence on the English language and its vocabulary in the Middle English period. The examples that I will present are taken from the ThePrologue of The Canterbury Tales of Geoffrey Chaucer who was an outstanding writer of this period. I collected several words that are very characteristic in the vocabulary of Chaucer, and I prepared a grouping according to several linguistic aspects. These examples will show very well that the vast majority of the vocabulary of Present-day English is composed of French loanwords. In order to understand this phenomenon, its causes and consequences, first of all I would like to define the status of loanwords in English and then to present their general characteristics in connection with other lexical units of the English language. Then, I would like to present the major charactaristics of Middle English including the main features of the London dialect and Chaucer’s vocabulary as well. Finally, with the help of concrete examples, taken from the The Prologue of The Canterbury Tales, I will examine in more detail in what measure the new lexical items were adopted by the English language.