Background <p>Managing synchronous cancers can be complex, often requiring multiple agents, which increases the risk of adverse drug reactions that could negatively impact patient survival. The risk of chemotherapy-induced infertility may also be higher, making pregnancy nearly impossible. The aim is to report long-term survival and successful pregnancy in a 30-year-old Nigerian woman with synchronous <i>BCR::ABL1</i> positive chronic myeloid leukemia and B-cell non-Hodgkin lymphoma.</p> Case presentation <p>The patient is a 30-year-old Nigerian woman referred by a general practitioner with a diagnosis of synchronous <i>BCR::ABL1</i> positive chronic phase chronic myeloid leukemia and B-cell non-Hodgkin lymphoma. The patient was managed concurrently with a combination of R-CHOP and imatinib mesylate and achieved remission; 5 years into therapy, the patient was lost to follow-up, only to present to the clinic 2 years later with a 1-month-old baby boy. Re-evaluation showed a loss of hematological and molecular remission in chronic myeloid leukemia but not in non-Hodgkin lymphoma. Breastfeeding was stopped and then resumed on imatinib. She subsequently went into remission and is currently doing well on imatinib.</p> Conclusion <p>Although managing multiple cancers in an individual may be challenging, we reported long-term survival and successful pregnancy in a 30-year-old Nigerian woman with concurrent chronic myeloid leukemia and non-Hodgkin lymphoma.</p>