IgA nephropathy (IgA-N) is the most common glomerulonephritis type globally. IgA-N is usually accepted as a kidney disease; however, IgA-N has been reported with infections, autoimmune diseases, and malignancies in the literature. In this report, we present a case of a 33-year-old man diagnosed with IgA nephropathy first and then with B-cell acute lymphoblastic leukemia (B-ALL). He was admitted to our hospital with complaints of nausea, vomiting, fatigue, and headache. Laboratory investigations revealed increased levels of blood urea nitrogen and creatinine, hypercalcemia, anemia, and thrombocytopenia. Kidney biopsy was performed, and IgA nephropathy was detected. Atypical lymphocytes and erythroblasts were present in the peripheral blood smear. Bone marrow biopsy was performed and demonstrated B-ALL. Kidney function tests normalized after 1 month of chemotherapy, including steroid treatment with intravenous fluid administration. In conclusion, it has been speculated that IgA nephropathy is associated with B-ALL.