In some low- and middle-income countries, separate vertical programmes deliver specific life-saving interventions but can fragment services. Strategies to integrate services aim to bring together inputs, organisation, and delivery of particular functions to increase efficiency and people's access. We examined the evidence on the effectiveness of integration strategies at the point of delivery (sometimes termed 'linkages'), including integrated delivery of tuberculosis (TB), HIV/AIDS and reproductive health programmes. To assess the effects of strategies to integrate primary health care services on healthcare delivery and health status in low- and middle-income countries. We searched The Cochrane Central Register of Controlled Trials (CENTRAL) 2010, Issue 3, part of the The Cochrane Library. www.thecochranelibrary.com, including the Cochrane Effective Practice and Organisation of Care Group Specialised Register (searched15 September 2010); MEDLINE, Ovid(1950 toAugust Week 5 2010)(searched10 September 2010);EMBASE, Ovid(1980 to2010 Week 35) (searched 10 September 2010); CINAHL, EBSCO(1980 to present) (searched 20 September 2010); Sociological Abstracts, CSAIllumina (1952 tocurrent) (searched 10 September 2010); Social Services Abstracts, CSAIllumina (1979 tocurrent) (searched 10 September 2010);POPLINE (1970 tocurrent) (searched 10 September 2010);International Bibliography of the Social Sciences, Webspirs(1951 to current) (searched 01 July 2008); HealthStar (1975 to September 2005), Cab Health (1972 to 1999), and reference lists of articles. We also searched the World Health Organization (WHOLIS) library database, handsearched relevant WHO publications, and contacted experts in the field. Randomised controlled trials, non-randomised controlled trials, controlled before and after studies, and interrupted time series analyses of integration strategies, including strengthening linkages, in primary health care services. Health services in high-income countries, private public partnerships, and hospital inpatient care were excluded as were programmes promoting the integrated management of childhood illnesses. The main outcomes were indicators of healthcare delivery, user views, and health status. Two authors independently extracted data and assessed the risk of bias. The statistical results of individual studies are reported and summarised. Five randomised trials and four controlled before and after studies were included. The interventions were complex.Five studies added an additional component, or linked a new component, to an existing service, for example, adding family planning or HIV counselling and testing to routine services. The evidence from these studies indicated that adding on services probably increases service utilisation but probably does not improve health status outcomes, such as incident pregnancies.Four studies compared integrated services to single, special services. Based on the included studies, fully integrating sexually transmitted infection (STI) and family planning, and maternal and child health services into routine care as opposed to delivering them as special 'vertical' services may decrease utilisation, client knowledge of and satisfaction with the services and may not result in any difference in health outcomes, such as child survival. Integrating HIV prevention and control at facility and community level improved the effectiveness of certain services (STI treatment in males) but resulted in no difference in health seeking behaviour, STI incidence, or HIV incidence in the population. There is some evidence that 'adding on' services (or linkages) may improve the utilisation and outputs of healthcare delivery. However, there is no evidence to date that a fuller form of integration improves healthcare delivery or health status. Available evidence suggests that full integration probably decreases the knowledge and utilisation of specific services and may not result in any improvements in health status. More rigorous studies ofdifferent strategies to promote integration over a wider range of services and settings are needed. These studies should include economic evaluation and the views of clients as clients' views will influence the uptake of integration strategies at the point of delivery and the effectiveness on community health of these strategies.