The atypical clinical features in multiple sclerosis (MS) have been rarely reported and suggest the possibility of an alternative diagnosis. The aim was to describe the clinical and demographic characteristics of MS patients who debuted with atypical symptoms and to estimate the sensitivity, specificity and positive predictive value (PPV) for MS diagnosis. A retrospective analysis of clinical records was performed. The following data were recorded: patients with MS diagnosis according to current diagnostic criteria at the time of diagnosis, type of symptom at the onset, time to second relapse, presence of oligoclonal bands (OCB) in cerebrospinal fluid (CSF) and radiological red flags on MRI. A descriptive and inferential analysis was performed using the chi square test, and sensitivity, specificity and PPV were calculated. Six hundred two patients were diagnosed with MS, of which 22 (3.65%) had an atypical clinical presentation. 54.5% were women. The mean age was 29 years (SD ± 11.7). The most common atypical symptom was peripheral facial palsy (27%). The PPV for atypical onset was 6.14%; p < 0.001. Sensitivity and specificity of these symptoms to MS diagnosis were 3.65% and 19%, respectively. In our research, the presence of atypical symptoms at the onset of MS was very low. Other diseases must be excluded, taking into account their low sensitivity, specificity and PPV.