Brucellosis is a neglected zoonotic bacterial disease in most of the developing world that has a significant impact on public health. The prevalence of brucellosis in livestock, particularly in large and small ruminants is variable in many countries and seems to remain high, especially amongst subsistence and small-scale livestock farmers. There are different factors that may influence the prevalence of brucellosis in large and small ruminants. This review is aimed at describing the most important factors that need to be taken into consideration for the planning and implementation of effective brucellosis control programmes. Common risk factors in the brucellosis development in small and large ruminant animals include species, age, sex, extensive or intensive production system, herd/flock size, mixed farming, introduction of new animals in the farms, breeding practice, hygiene, absence of vaccination, and awareness of the disease. This review suggests that different risk factors might have various impacts on brucellosis seroprevalence that need to be addressed in epidemiological studies in different farming systems.