Eleven patients with Welander distal myopathy were subjected to detailed sensory testing including measurements of perception thresholds for vibration and temperature in both hands and feet. The threshold values were compared with normal, age-corrected values and also with data from an age-matched control group consisting of patients with antecedent poliomyelitis with the same degree of paresis. The screening examination indicated impaired thermal sensibility in all 11 patients and impairment for at least one other sensory modality in 9 patients. In comparison with age-corrected normal values, the measured warm-cold difference limen was abnormal in the feet of 9 patients and the vibratory threshold at least at one test point in 6 patients. When compared with the data from the paretic controls, the thermal abnormality was significant with regard to warm and cold thresholds, the warm-cold difference limen and the heat pain threshold. The vibration threshold abnormality was significant in the feet. It is concluded that sensibility impairment is present in Welander's myopathy indicating a peripheral sensory neuropathy involving both unmyelinated (C-fibers) and myelinated fibers.