Publishers of graded readers have now created audiovisual materials to accompany many of their graded reader titles and online libraries such as Xreading (www.xreading.com) are making it easier for students to listen to or read-while-listening to comprehensible input. Apart from Gobel (2011) and more recently Chang and Millet (2014, 2015 & 2016), investigations into the learning effects of students reading-while-listening to graded reader audiobooks remains a very under-researched area of extensive reading. This paper presentation reports on an experimental study interested in the development of English language learners’ listening skills. More specifically, how increased input via extensive reading and reading-while-listening affects listening skills. Changes in listening performance were compared among three groups of students (N=75) studying at a Japanese university, namely: (1) a treatment group who read 100,000 words of self-selected graded readers (n=21 ), (2) a treatment group who read-while-listening to over 100,000 words of self-selected graded reader audio books (n=29), and (3) a control group who did not receive any extra English input (n=25).