During Valsalva’s manoeuvre the following neck masses could be seen: laryngocele, external laryngeal diverticle, pharyngocele, jugular vein phlebectasia, apical lung herniation, superior mediastinal cyst or tumour. In the present paper three children with neck mass visible during Valsalva’s manoeuvre are presented. In a child with neck mass appearing on the right lateral neck, an internal jugular vein phlebectasis was found. In two children the neck mass appeared in jugulum, above the sternum. In one child, the clinical finding pointed to an apical lung herniation (crepitation in the neck mass); in another child, herniation of the thymus was presumed. As these neck masses are asymptomatic, parents rarely consent to procedures which are intended to elucidate the nature of these formations. In early childhood, it is difficult to achieve conditions for deep inspiration, to register the formation on time, and make an accurate diagnosis. Descriptors: VALSALVA MANOEUVRE; DIAGNOSIS; CHILD; NECK