Brain-Computer Interface (BCI) is a relatively young research field which has seen a growing interest with associated number of publications over the last two decades. In this study we present the first bibliometric analysis of the BCI literature (1990–2008) from the Thomson Reuters's Institute for Scientific Information (ISI) Web of Knowledge. Thus, the main objectives of this bibliometric study are: 1) to explore the growth of BCI literature, 2) to assess if it follows Lotka's law of scientific productivity, 3) to identify authors, groups and countries contributing the most to BCI, 4) to reveal the characteristic of citation for the BCI literature, and finally, 5) to determine the core journals that published substantial portions of the literature on BCI. Results indicate that BCI literature follows a power law growth, has an average author count of 3.9 and an average page count of 7.09. More than half (52.73%) of the BCI literature is never cited, and 14 papers have been cited more than 100 times. The 3 most productive authors are leading BCI research groups, in Austria, Germany and the USA.