The oligoclonal profile of immunoglobulins is reflected by the presence of more than two narrow monoclonal peaks on serum protein electrophoresis, corresponding to the synthesis of several Immunoglobulin (Ig) idiotypes and isotypes by selection of a small number of plasma cells. The aim of this study is to elucidate the etiologies of the oligoclonal profile detected in the gamma globulin zone during the electrophoretic analysis of serum proteins of patients hospitalized and consulting at the Ibn Rochd University Hospital in Casablanca. This is a retrospective study spread over 8 months from January 1 to September 1, 2020, focused on the analysis of electrophoretic profiles of sera collected from hospitalized and consulting patients at CHU Ibn Rochd. The PES was carried out using the capillary electrophoretic technique on a capillarys automated system, and total protein determination by Biuret colorimetric method on an Architect automated system. Immunofixation was performed on agarose gel using the Hydrasys Sebia automated system, and immunofixation on capillarys 2 Flex piercing. Our study revealed 2 oligoclonal profiles: The first from a patient hospitalized in the nephrology department for nephrotic syndrome and renal failure, the results of his work-ups were as follows: serum protein immunosubtraction showed the presence of an IgG kappa immunoglobulin and an IgM lambda, and histopathological examination of the kidney showed glomerulonephritis. IgM lambda, and histopathological examination of the kidney showed glomerulonephritis stage 1. The second patient was admitted to the hematology clinic for anaemia and bone pain, His work-up was as follows: serum protein immunofixation showed IgA kappa immunoglobulin, and urine protein immunofixation showed free kappa/kappa light chain. Myelogram revealed multiple myeloma. The oligoclonal profile must be interpreted on a case-by-case basis according to the context of each patient, to reveal damage to the immune system and ensure immune system and ensure therapeutic follow-up.