Different living organisms are used as applicable bioindicators to determine heavy metal pollutions. Recent studies have shown that helminths parasites can be used as efficient environmental sentinels. This study aimed to evaluate Fasciola hepatica and Dicrocoelium dendriticum as bioaccumulators of lead (Pb), chromium (Cr), cadmium (Cd), copper (Cu). For this work. A total of 50 samples (F. hepatica, D. dendriticum, and livers from the infected and uninfected sheep, each of 10 samples) were collected from sheep slaughtered in Tabriz abattoir. One gram of each sample was incinerated and analyzed by Flame Atomic Absorption Spectrometry. The analysis of samples showed that Pb, Cr and Cu values in F. hepatica were higher than those in D. dendriticum, but only the differences of Pb and Cu were significant. The values of heavy metals in F. hepatica were significantly higher than those in the infected livers (except for Cd), while in D. dendriticum, Cr and Cd were only higher. Based on metal levels in livers, it was found that bioconcentration factors (BCFs) of Cr, Pb and Cu for F. hepatica were much more than one, and BCFs of these three metals between two flukes were statistically significant. This study indicated that F. hepatica had a higher bioindicator potential than D. dendriticum to evaluate environmental pollutants by some metals.