Objective. To find the correlation between neurophysiological and neurosonographic (NSG) parameters of the facial nerve of children with idiopathic neuropathy of the facial nerve (NLN) in the acute period with good and poor prognosis of recovery of facial nerve function. Material and methods. Sixty-five children with NLN (mean age 11.5±4.9 years) and 57 children of control group (mean age 12.5±5.2 years) were examined. All children with NLN were studied using NSG with the measurement of the diameter of the facial nerve in the area of processus stylomastoideus and in the parotid gland. Stimulation electroneuromyography of the facial nerve with the registration of the M-response from the m. orbicularis oculi and evaluation of the degree of paresis of facial muscles using the 6-point House—Brackmann scale on the 10—15 day were performed. On the 30th day after manifestation of paresis, children with NLN were divided into two groups: the good recovery group 1 (n=54) and the poor prognosis recovery group (n=11). Correlation between NSG and electroneuromyography indicators with good and poor prognosis of recovery of facial nerve function was analyzed. Results and conclusion. Based on the results obtained, 85% sensitivity and 77% specificity of measuring the diameter of the facial nerve using NSG in predicting poor prognosis of recovery of facial nerve function was shown. Normative and thresholds NSG parameters of the facial nerve in children were obtained.