The objective of the study was to examine the effectiveness of a customised personal digital assistant (PDA) as a cognitive aid for people with acquired brain injury, using a randomised parallel-group study. The participants were 34 patients with acquired brain injury in a cognitive rehabilitation setting. The experimental group used a customised PDA, while the control group received care-as-usual (paper-and-pencil aids). Measurements were conducted at baseline (T0), after 8 hours of training (T1), after 16 hours of training (T2), and at 5-month follow-up (T3). The main outcome was the attainment of individualised goals. Both groups showed a significant increase in goal attainment (GAS) (p<.001). There were no significant differences between the groups at T1 or T2 on any of the other outcome measures. It was concluded that the customised PDA was as effective as paper-and-pencil aids, and may therefore serve as a useful alternative when choosing the optimal rehabilitation strategy for a patient.