Background: Liver cancer is a highly lethal cancer with 5 year survival rate of about 18%. This cancer is a leading cause of death in many countries. As there is not a comprehensive population base study on liver cancer mortality rates by cause in national and provincial level in Iran. We aimed to estimate the liver cancer mortality rate, its patterns, and temporal trends during 26 years by sex, age, geographical distribution, and cause. Methods: We used the Iranian death registration system (DRS), in addition to demographic and statistical methods, to address the incompleteness and misclassification and uncertainty of death registration system to estimate annual liver cancer mortality rate. Direct age standardized approach was applied using Iran national population 2015 as a standard population to facilitate the comparison between the provinces. Results: Liver cancer age standardized mortality rate in Iran increased by more than four times from 1.18 (95% uncertainty interval; 0.86 to 1.61) deaths per 100,000 person in 1990 to 5.66 (95% uncertainty interval; 4.20 to 7.63) deaths per 100,000 person in 2015. Male to female age adjusted mortality ratio changed from 0.87 to 1.82 during the 26 years of the study. With increasing age, liver cancer mortality rate increased in both sex and all provinces. At provincial level, the province with highest mortality rate have 2.96 times greater rate compare to the lowest. Generally, about 71% of mortality at national level is due to hepatitis B and C infection. Conclusions: In order to reduce liver cancer mortality rate, it is recommended to control main risk factors including chronic hepatitis infections. Because of the growing rate of mortality from liver cancer, augmenting life expectancy, and increasing number of the elderly in Iran, policy makers are more expected to adopt measures including hepatitis B vaccination or hepatitis C treatment.