The thalassemias are the most common single gene disorder in the world. Nowadays, the average life expectancy of patients in developed countries has increased significantly, while, there was an increase of complications. We aimed to investigate peripheral neuropathy and myopathy in this patient group using a neurophysiological study. We performed nerve conduction studies and electromyography of upper and lower extremities on 36 beta-thalassemia major (β-thal) patients. The electrophysiological findings were correlated with demographic data and laboratory parameters of the disease. Patients with β-thal present polyneuropathy or myopathy at (50%). Polyneuropathy was detected in (38.9%) and myopathy in (27.8%), while polyneuropathy and myopathy were present at (16.7%) with an overlap of the diseases in 1/3 of the patients. There was not a statistically significant correlation of polyneuropathy and myopathy with age, sex, splenectomy, nor with respect to laboratory parameters, hemoglobin, and ferritin. However, there was a statistically significant correlation of polyneuropathy and myopathy with iron overload, as recorded by the magnetic resonance imaging (MRI) of the heart and the liver. Our findings suggest that iron overload plays a key role in the pathogenesis of polyneuropathy and myopathy in β-thal patients, and performing heart and liver MRI for the prediction of such lesions in an annual basis is warranted.