The aim of this study was to describe biological features and aetiology of monoclonal gammopathy diagnosed during a 10-year period in the biochemistry department of the Moroccan Military Hospital Mohamed V in Rabat. The study was performed from 1 January 2000 to 31 December 2009. The records of 261 patients living in the Rabat area in which either serum protein electrophoresis and serum and/or urine immunofixation were performed at the biochemistry department of Military Instruction Hospital in Rabat were analysed. A cohort of 182 (70%) men and 79 (30%) women, the mean ± SD (range) ages were 60.21 ± 12.56 years. All patients were Caucasian. Electrophoresis found that 211 (80.84%) of the patients had a monoclonal gammopathy. Immunofixation confirmed that 251 (96.17%) patients had a monoclonal band in serum. In our cohort, MM was the most frequent diagnosis, our patients were late diagnosed.