The purpose of this research is to determine the effects of home-based programmes aimed specifically at improving developmental outcomes for preschool children from socially disadvantaged families. The authors searched the following databases between 7 October and 12 October 2010: Cochrane Central Register of Controlled Trials (CENTRAL) (2010, Issue 4), MEDLINE (1950 to week 4, September 2010), EMBASE (1980 to Week 39, 2010), CINAHL (1937 to current), PsycINFO (1887 to current), ERIC (1966 to current), ASSIA (1987 to current), Sociological Abstracts (1952 to current), Social Science Citation Index (1970 to current). They also searched reference lists of articles. The authors included seven studies, which involved 723 participants. They assessed four of the seven studies as being at high risk of bias and three had an unclear risk of bias; the quality of the evidence was difficult to assess as there was often insufficient detail reported to enable any conclusions to be drawn about the methodological rigour of the studies. Four trials involving 285 participants measured cognitive development and they synthesised these data in a meta-analysis. Compared to the control group, there was no statistically significant impact of the intervention on cognitive development (standardised mean difference (SMD) 0.30; 95% confidence interval -0.18 to 0.78). Only three studies reported socioemotional outcomes and there was insufficient data to combine into a meta-analysis. No study reported on adverse effects. This review does not provide evidence of the effectiveness of home-based interventions that are specifically targeted at improving developmental outcomes for preschool children from socially disadvantaged families. Future studies should endeavour to better document and report their methodological processes. Search Strategies are appended. (Contains 1 figure.) [Funding for this paper was provided by the Queen's University Belfast Centre for Effective Education and the Research and Development Office, Northern Ireland.]