Background: Late diagnosis of HIV is a problem of international and national relevance. Despite the availability of HIV testing in primary health care, it is often performed too late. Aim: To identify facilitators and barriers to early HIV testing in primary health care. Methods: Four databases of nursing, psychological, biomedical, and health related professions areas were examined with a review protocol. Results were grouped into two main subjects: facilitators and barriers occurring among the population, among health care workers, and within primary health care centers. Results: Perception of risk behaviors, self-care, social support, trust, confidentiality of the examination, the offer of the examination, and the knowledge of early treatment have been recognized as facilitators for taking the exam. The lack of information about the test and the disease are recognized as the main barrier to access the test. This information is a cornerstone to design and implement strategies to increase the number of people taking voluntarily HIV testing.