Abstract Background Community Health Workers are widely utilised in low- and middle-income countries and may be an important tool in reducing maternal and child mortality; however, evidence is lacking on their effectiveness for specific types of programmes, specifically programmes of a preventive nature. This review reports findings on a systematic review analysing effectiveness of preventive interventions delivered by Community Health Workers for Maternal and Child Health in low- and middle-income countries. Methods A search strategy was developed according to the Evidence for Policy and Practice Information and Co-ordinating Centre’s (EPPI-Centre) guidelines and systematic searching of the following databases occurred between June 8 – 11 th , 2012: CINAHL, Embase, Ovid Nursing Database, PubMed, Scopus, Web of Science and POPLINE. Google, Google Scholar and WHO search engines, as well as relevant systematic reviews and reference lists from included articles were also searched. Inclusion criteria were: i) Target beneficiaries should be pregnant or recently pregnant women and/or children under-5 and/or caregivers of children under-5; ii) Interventions were required to be preventive and delivered by Community Health Workers at the household level. No exclusion criteria were stipulated for comparisons/controls or outcomes. Study characteristics of included articles were extracted using a data sheet and a peer tested quality assessment. A narrative synthesis of included studies was compiled with articles being coded descriptively to synthesise results and draw conclusions. Results A total of 10,281 studies were initially identified and through the screening process a total of 17 articles detailing 19 studies were included in the review. Studies came from ten different countries and consisted of randomized controlled trials, cluster randomized controlled trials, before and after, case control and cross sectional studies. Overall quality of evidence was found to be moderate. Five main preventive intervention categories emerged: malaria prevention, health education, breastfeeding promotion, essential newborn care and psychosocial support. All categories showed some evidence for the effectiveness of Community Health Workers; however they were found to be especially effective in promoting mother-performed strategies (skin to skin care and exclusive breastfeeding). Conclusions Community Health Workers were shown to provide a range of preventive interventions for Maternal and Child Health in low- and middle-income countries with some evidence of effective strategies, though insufficient evidence is available to draw conclusions for most interventions and further research is needed.