This paper reports a systematic review of the quasi-experimental literature in the field of adult literacy and numeracy, published between 1980 and 2002. We included 27 controlled trials (CTs) that evaluated strategies and pedagogies designed to increase adult literacy and numeracy: 18 CTs with no effect sizes (incomplete data) and 9 CTs with full data. These nine trials are examined in detail for this paper. Of these nine trials, six evaluated interventions in literacy and three evaluated interventions in literacy and numeracy. Three of the nine trials showed a positive effect for the interventions, five trials showed no difference and one trial showed a positive effect for the control treatment. The quality of the trials was variable, but many of them had some methodological problems. There was no evidence of publication bias in the review. There have been few attempts to expose common adult literacy or numeracy programmes to rigorous evaluation and therefore in terms of policy and practice it is difficult to make any recommendations as to the type of adult education that should be supported. In contrast, however, the review does provide a strong steer for the direction to be taken by educational researchers: because of the present inadequate evidence base rigorously designed randomised controlled trials and quasi-experiments are required as a matter of urgency.