PURPOSEThe epidemiology of cancer in adolescents and young adults (AYAs) is distinct and underinvestigated. Therefore, we investigated the incidence of cancer in AYAs in Jordan.PATIENTS AND METHODSWe accessed all records submitted to the Jordan Cancer Registry between 2000 and 2017. We included all patients, age 15-39 years, who were ordinarily resident in Jordan. We then calculated frequencies, age-adjusted incidence rates (AAIRs), and annual percentage changes (APCs) and performed subgroup analyses by biologic sex, age subgroups, and site (SEER AYA site recode/WHO 2008). We also performed site-specific trend analyses using joinpoint models.RESULTSWe identified 14,115 eligible patients, of whom 1,531 (10.8%), 4,278 (30.3%), and 8,306 (58.8%) were 15-19, 20-29, and 30-39 years old at diagnosis, respectively. The numbers of male and female AYAs were 5,792 (41.0%) and 8,323 (59.0%), respectively. The crude number of cases increased from 654 in 2000 to 954 in 2017 (APC, 2.6%). The overall AAIR ranged from 32.3 in 2000 to 24.3 in 2017 (APC, –1.7%). The AAIR was 27.6 over the full study period and was higher in females (34.1) than in males (21.6). Carcinomas, lymphomas, and leukemias were the most common cancers. The incidence rates of the majority of cancers trended downward over the study period.CONCLUSIONThe incidence of cancer in AYAs in Jordan is relatively low and declining. However, the absolute number of cases is increasing because this downtrend does not offset the effect of a high population growth rate; almost a 1,000 cases of cancer are now diagnosed every year, which represents a significant increase in the burden of cancer in a developing country with limited healthcare resources.