The present study examines the long-term effects of a 10-session cognitive behavioural group therapy for patients with mild cognitive impairment (MCI) and their significant others 6 to 8 months after completion of the intervention. Forty-seven MCI patients and 47 significant others participated in the follow-up assessment. Results of the RAND-36, Illness Cognition Questionnaire, IQCODE, GDS-15 and Sense of Competence Questionnaire at follow-up were compared with the post-intervention assessment. Our findings showed that the increased level of acceptance in the MCI patients was maintained at follow-up, with an increased insight into their cognitive decline compared with post-intervention assessment (p < 0.001). In both the patients and the significant others, helplessness and wellbeing were worse at follow up (p < 0.05), but sense of competence increased in the significant others (p < 0.05). These results indicate a need for extension of the support after completion of the program, for example by providing regular booster sessions.