Background and Aim. Hematological disorders (HD) affect millions of people annually worldwide. Nutritional care is essential in acute or chronic HD, especially in controlling metabolic and gastrointestinal disorders that affect the nutritional status of individuals. Methods. A bibliographic survey was carried out between 2020 and 2022 using two databases: PubMed/MEDLINE and Scientific Electronic Library Online (SciELO) and the information source Academic Google, irrespective of language or geography. Results. In the first nutrition consultation (FNC), there should be an investigative direction focused on nutritional interventions in the short, medium, and long term. The record in the patient’s medical record is relevant for carrying out the consultation, according to the recommendations of the normative councils of medicine and nutrition. The main steps to be followed are the investigation of the presence of food allergies and intolerances; the drugs/nutritional supplements in use; changes in the digestive tract; the presence or absence of picamalacia; and socioeconomic and lifestyle data. In addition, it is necessary to carry out laboratory evaluations, semiological assessment, anthropometric assessment, and assessment of food consumption. In the end, the nutritional approach should be composed of calculation of energy and macronutrient and micronutrient needs, intervention in nutritional status deviations, nutritional guidelines, and nutritional therapeutic planning of return, focusing on adherence to treatment. Conclusion. The first nutrition consultation may represent investigative steps that help the clinical nutritionist in the management, allowing a longitudinal and specific nutritional therapeutic planning for patients assisted in large reference centers for hematological disease.