Electrolyte imbalances can frequently occur among patients with cancer. Hypomagnesemia and hypokalemia are side effects of certain chemotherapies, including cisplatin, cetuximab, eribulin, and ifosfamide. When patients concurrently receive chemotherapy and take medications that cause hypomagnesemia or hypokalemia, electrolyte imbalances are amplified. Provider and patient education are vital to identifying and treating these conditions in a timely manner. If medication usage depletes electrolytes, repletion through diet and supplements is essential. In symptomatic cases of electrolyte deficiency, oral and IV formulations of potassium and magnesium are options for treatment. This article discusses the importance of identifying and understanding the etiologies, symptoms, and treatment modalities of hypomagnesemia and hypokalemia.