We examined the effect of surrounding information on reading text that was scrolling from right to left inside a fixed window. In Experiment 1, participants adjusted the scrolling rate so that they could comfortably read the text scrolling in the window. Above or below the window, a character was flashed with a random stimulus onset asynchrony (SOA). The results showed that the comfortable scrolling rate increased with the size of the window (i.e, the number of characters simultaneously displayed in the window). Moreover, the comfortable scrolling rate decreased when discrimination of the flashed character was required. In Experiment 2 a character was flashed above or below the right or left end of the window. The results showed that the increase of the comfortable scrolling rate with window size was less effective when the character was flashed above or below the right end of the window. These results are discussed in relation to the role of eye movements when reading scrolling text in the presence of surrounding information.