Introduction: Few studies document the information searching behaviour of users with cognitive impairments. This paper therefore addresses the effect of dyslexia on information searching in a database with no tolerance for spelling errors and no query-building aids. The purpose was to identify effective search interface design guidelines that benefit dyslexic users. Method: Twenty dyslexic students and twenty controls solved ten predefined search tasks in the Norwegian library catalogue Bibsys Ask. Screen-recording and eyetracking were used to observe search behaviour. Analysis: The statistical analysis software SPSS was used for quantitative analyses, SMI BeGaze was used for qualitative analysis of the search behaviour. Results: Dyslexic students took longer and formulated more queries per task than the controls. Further, they submitted shorter queries, made more misspellings and relied more upon external resources. There were no differences in problem solving approaches across the two groups except that the dyslexic students used external Websites more. Conclusions: The results of this study indicate that dyslexia has a negative impact on search performance in systems with no tolerance for errors and no query-building aids. Several guidelines are suggested based on the observed information searching behaviour to accommodate users with dyslexia.