This study investigated how common online text affects reading performance of elementary school-age children by examining the actual and perceived readability of four computer-displayed typefaces at 12- and 14-point sizes. Twenty-seven children, ages 9 to 11, were asked to read eight children's passages and identify erroneous/substituted words while reading. Comic Sans MS, Arial and Times New Roman typefaces, regardless of size, were found to be more readable (as measured by a reading efficiency score) than Courier New. No differences in reading speed were found for any of the typeface combinations. In general, the 14-point size and the examined sans serif typefaces were perceived as being the easiest to read, fastest, most attractive, and most desirable for school-related material. In addition, participants significantly preferred Comic Sans MS and 14-point Arial to 12-point Courier. Recommendations for appropriate typeface combinations for children reading on computers are discussed.