The assessment of a patient's body fluid status is a challenging task for modern clinicians. Ultrasonography has numerous advantages, the most important being reproducibility and bedside monitoring of the patient. The examination is quick and has a significant diagnostic value. We reviewed the literature to assess the possibility of using ultrasound methods for evaluating body fluid status. The search of PubMed and Medline databases was performed up to February 2019. Data from published reports and clinical observations show that the quick and noninvasive ultrasound examination facilitates the assessment of intravascular volume status and that the results correlate with other modalities, including invasive methods. Ultrasound enables physicians to determine the baseline status of hydration and to monitor the patient during fluid therapy. Additionally, it allows an assessment of asymptomatic patients, patients who are well adapted to chronic oxygen deficiency, and those who develop pulmonary congestion secondary to congestive heart failure or chronic kidney disease. The development of a protocol for an ultrasound assessment of the volume status would significantly facilitate the everyday practice of internal medicine specialists.