Recurrent pregnancy loss (RPL) is one of the most frustrating problems in reproductive medicine because the etiology is often unknown. Recent studies suggest the role of environmental chemicals in the pathogenesis of RPL. The objective of this study was to investigate the possible role of some heavy metals (lead and cadmium) as risk factors of RPL by determining their levels in normal and unexplained RPL pregnancies. This cross-sectional study included 47 cases with definite diagnosis RPL and 30 pregnant controls with normal obstetric history. Blood levels of heavy metals (lead and cadmium) were measured using atomic absorption spectrometer with graphite furnace. The results showed significantly higher levels of lead and cadmium in RPL group than those levels in the control group. These levels were higher in women who lived in urban areas and those exposed to cigarette smoke than women who lived in rural areas and non smokers, respectively. In conclusion: This study suggests that high blood levels of lead and cadmium are associated with increased risk of RPL.