Patients with chronic kidney disease (CKD) have a high prevalence of left ventricular hypertrophy (LVH), which increases as kidney function decreases. LVH pathophysiology is complex, making it difficult to generalise its evolution in CKD. Therefore, early detection and prevention of risk factors are critical. Assessment and management of volume status can minimise cardiovascular complications including LVH. We retrospectively investigated the associations between fluid overload and LVH in patients with stage 5 CKD not undergoing dialysis in prospective cohort of 205 patients (age: 59.34 ± 13.51 years; women: 43.4%). All patients, free of intrinsic heart disease, were assessed for relative overhydration/extracellular water (OH/ECW) by bioimpedance spectroscopy. Our results show that markers reflecting fluid balance were significantly higher in the LVH group and as OH/ECW increased, the left ventricular mass index (LVMI) trended higher. Furthermore, our results show that systolic blood pressure, serum phosphorus levels, and OH/ECW were independently associated with LVMI and that OH/ECW was independently associated with LVH. Structural and functional evaluation of the heart using echocardiography and volume status assessment using bioimpedance should be performed simultaneously in patients with early-stage CKD, even in those without evident cardiovascular disease.