Epidemiological pattern of death and causes of death in registered immigrants of Northeast Iran during the 2013–2023: a cross-sectional study

International migration has increased in recent years and yet there is limited information about immigrant mortality. The present study aimed to investigate the epidemiological pattern of death and their causes among registered immigrants in Mashhad city, northeast Iran. In this cross-sectional study, data on deceased Afghan immigrants registered according to the International Classification of Diseases (ICD-10) were extracted from the system of registration and classification of the causes of death of Iran for deaths due to causes related to non-communicable diseases, communicable diseases, maternal/neonatal causes, injuries and unknown along with subgroups of each cause during the years 2013–2023. The variables analyzed included age, gender, date and cause of death. Patterns of death and age/gender standardized mortality rates were calculated. Data analysis was performed using Stata software. Data from 10,777 deaths were analyzed. The crude mortality rate was 3.05 per 1,000 population per year, while the age and gender standardized mortality rate (using the direct method and WHO 2000–2025 standard population) was 5.42 per 1,000 (95% CI: 5.31–5.54). Over this decade, non-communicable diseases were the leading cause of death among immigrants, accounting for 51.11%, followed by communicable diseases (24.27%), maternal/neonatal causes (10.44%), injuries (9.62%) and unknown causes (4.56%), respectively. Maternal/neonatal causes were more prevalent in males with 617 cases than females with 508 cases. Injuries were more common in males (n = 831) and predominantly affected the 20–40 age group with 40.04%. Among non-communicable diseases, circulatory system diseases (n = 3396) were the most frequent, followed by neoplasms (n = 839). A significant difference was observed between the occurrence of each cause of death and both age (p < 0.001) and gender (p < 0.001). Mortality due to non-communicable diseases, particularly circulatory system diseases and neoplasms, was higher among immigrants than other causes of death. Understanding and recording comprehensive and accurate data on the causes of death in migrant populations is crucial. Also, Addressing the health needs of migrants remains a major challenge due to the various risks associated with migration. Therefore, clinicians, health managers and policymakers involved in immigrant health require enhanced knowledge as a foundation for evidence-based care and informed decision-making.