Intellectual Function Training (IFT) is an occupational therapy method for remediating cognitive functions in patients with acquired brain damage and has been presented in a previous paper. It has been evaluated by comparing a group of trained patients (n = 13) using the IFT method with a control group (n = 13) which underwent conventional rehabilitation. The trained group received IFT for 40 min each day, 5 days a week for about three months. Age, education and neurological status did not differ between the groups. The measurement methods of evaluation were Intellectual Function Assessment (IFP) and three psychometric test batteries. At the beginning of the study there was no significant difference in any subtest between the two groups. After the training period there was a significant difference of at least p less than 0.05 between the trained and the control group in the IFP battery, except for the Long-term Memory subtest. The improvement for the trained group was evident six months later at the time of the follow-up measurement, clearly indicating a significant difference between the groups. In one psychometric subtest a significant difference of p less than 0.01 was found. Within the experimental group over the study time there was a slight increase in performance which was notable in seven of the psychometric subtests p less than 0.05-p less than 0.001. The positive effect of IFT is considered to be specific for the type of task in which the patients were trained, while evidence of the effect on general intellectual function is inconclusive.(ABSTRACT TRUNCATED AT 250 WORDS)