Given that the research area of cognitive intervention studies in the aging population is growing rapidly, it is important to review and gauge more recent intervention studies, in order to determine the evidence for the effectiveness of cognitive interventions. The purpose of the present review was to update the recent systematic reviews of Papp et al. (2009) and Martin et al. (2011), to evaluate the effectiveness of cognitive interventions in healthy older adults and people with MCI, by taking into account the methodological quality of the interventions studies. A systematic review of randomized controlled trials (RCT) and clinical studies published between August 2007 and February 2012 in Pubmed and PsychINFO was performed. The quality of the included RCTs was assessed according to the CONSORT criteria for RCTs. A total of thirty-five studies were included; twenty-seven RTCs and eight clinical studies. The content of the intervention studies differed widely, as did the methodological quality of the included RCTs, but was considerably low with an average of 44% of the Consort items included. The results show evidence that cognitive training can be effective in improving various aspects of objective cognitive functioning; memory performance, executive functioning, processing speed, attention, fluid intelligence, and subjective cognitive performance. However, the issue whether the effects of cognitive interventions generalize to improvement in everyday life activities is still unresolved and needs to be addressed more explicitly in future research. (c) 2012 Elsevier B.V. All rights reserved.