Few cases of eosinophilia associated with B cell acute lymphoblastic leukemia (B-ALL) have been reported. This study reported a 16-year-old male patient diagnosed with B-ALL and hypereosinophilia. He was admitted to the emergency department (ED) with urticaria and generalized itching. On initial examination, the skin was wholly erythematous, and urticarial lesions were scattered throughout the body. Peripheral blood smear (PBS) was examined, and eosinophils were seen in different fields. However, blast cells were not seen in the PBS. In bone marrow examination, terminal deoxynucleotidyl transferase (TdT)-positive and CD20-positive lymphoid blasts were reported along with eosinophilia. In immunohistochemical (IHC) staining, results were within normal limits for the fibroblast growth factor receptor 1 (FGFR1), platelet-derived growth factor receptor alpha (PDGFRα), and platelet-derived growth factor receptor beta (PDGFRβ) genes expressions. Moreover, no breakpoint cluster region (BCR)/Abelson murine leukemia 1 (ABL1) mRNA transcripts and no Janus kinase 2 (JAK2) V617F mutation were detected. Eventually, the B-ALL diagnosis was confirmed for the patient, and he was started on the Berlin-Frankfurt-Münster (BFM) chemotherapy regimen. The patient was transferred to another facility and is continuing his treatment there.