Objective: To characterize by flow cytometry and cytogenetic studies the patients with multiple myeloma. Methods: descriptive and observational study, carried out in a highly complex institution in the city of Medellín – Colombia. The patients over 18 years of age with a diagnosis of multiple myeloma were included. The collection of information was performed by review of clinical histories and the data obtained was analyzed in the IBM SPSS version 24 program. Results: 89 patients were included: 52.8% were male, 33,7% had between 61 and 70 years, the median hospitalization time was 17 days. The most frequent clinical manifestations were anemia, predominantly lumbar bone pain and kidney failure in 78%, 61.8% and 58.4% of the patients respectively. The CD38 + and CD56 markers+ were the most common immunophenotype, present in 39.3% of patients. Regarding clinical outcomes, 70.8% of the patients were discharged and 28.1% died, with the progression of the multiple myeloma being the main cause of death in 36% of cases. Conclusion: Multiple myeloma is a pathology that affects adults, it leads to an increase in hospital stay, nonspecific symptoms such as weight loss, edema, bone pain and pathological fractures, which affect quality of life and increase the mortality of people. Thanks to flow cytometry, this study found that the so-called aberrant immunophenotype was the most common in the included population.