Background: Zorzi et al. (2012, Proc. Natl. Acad. Sci. U.S.A., 109, 11455) found evidence that extra-large letter spacing aids children with dyslexia, but the evidence for the coloured overlays is contradictory (e.g., Henderson et al., 2013, "J. Res. Special Educ. Needs," 13, 57; Wilkins, 2002, "Ophthalmic Physiol. Opt.," 22, 448), and possible combined advantages have not been identified. Aims: To investigate whether extra-large letter spacing or coloured overlays can alleviate reading problems in dyslexic adults. Sample: The participants were 24 dyslexic and 24 non-dyslexic university students, matched for age and fluid intelligence. Methods: The reading speed and the errors made by a dyslexic and a control group were measured in four conditions: with and without coloured overlays and with normally and largely spaced texts. Results: Large letter spacing improves the reading speed in general, as well as improves the reading accuracy in dyslexic readers. Conclusions: The results support the positive effect of letter spacing on reading performance.