Background: The epidemiology of cancer among adolescents and young adults (AYA) has been a relatively neglected topic, particularly in the developing countries. The main objective of this study was to present the epidemiology of cancer among this subpopulation in Haiti’s largest cancer program. Methods: A retrospective study was conducted on patients aged 15 to 39 years old with pathological and/or clinical diagnosis of cancer at the cancer clinic of Innovating Health International (IHI) in Port-au-Prince, Haiti from January 2016 to December 2019. The chart review collected variables such as age, gender, date of diagnosis, cancer type and outcome to present this epidemiological profile of AYA cancers. Results: Among the two thousand two hundred and ninety-eight (2298) cancer cases managed during this study period, 20.1% (n = 461) were adolescents and young adults. 82% of these patients were female and 18% male. 25.2% (n = 116) were less than 30 years old. Breast cancer was the most common type (n = 222, 48.2%%), followed by gynecological cancers (n = 70, 15.1%) with cervical cancer representing 61.4% of the cases (n = 43), hematological malignancies (n = 44, 9.5%) with lymphomas (n = 31) as the most common type, sarcomas (n = 43, 9.3%), head and neck cancers (n = 24, 5.2%), gastrointestinal cancers (n = 22, 4.8%), cutaneous cancers (n = 10, 2.2%), urological cancers (n = 5, 1.1%), thyroid cancer (n = 5, 1.1%) and CNS tumors (n = 2, 0.4%). 3.0% of the AYA patients (n = 14) presented with a cancer of unknown primary (CUP). In the < 30 y/o subgroup blood cancers, breast cancer, sarcomas, and head and neck malignancies were respectively the most common types, while in the ≥ 30 y/o subgroup, breast and gynecological cancers were the most common, followed by sarcomas, GI and blood cancers. No case of lung cancer was received for the AYA population. The overall mortality rate was 30.6% and 12.8% of the patients were lost to follow-up. Conclusions: Cancers among AYA patients represented 20.1% of the cancer population, with a different epidemiological profile for the < 30 y/o and ≥ 30 y/o subgroups. The CNS tumors, leukemias and urological cancers were most likely under-represented due to low referral, misdiagnosis or early mortality.