By applying the most stringent principles of the comparative-historical method nearly two hundred Burushaski words are analysed which display firm Indo-European correspondences that do not originate from an Indo-Aryan or Iranian source. The etymologies show consistent and regular phonetic correspondences and highly specific semantic concordance with the ancient Balkan languages (most notably Phrygian and Thracian) and with Balto-Slavic. The basic and compact semantic fields to which the analysed vocabulary belongs (body parts, age and family relations, agriculture, plant names, sheep-farming, geographical features, names of vessels and tools, core adjectives and verbs) together with the derivational, grammatical and structural correspondences point to a rather close relationship and affinity of Burushaski with these linguistic groupations. It can be concluded that there is an ancient Indo-European layer in Burushaski which indicates an early relationship or contact in its history with the Southern (Aegean) branch of I.E. on the one hand and with the Northern I.E. group on the other, with which it shows remarkable and very close correspondences. Further systematic study of Burushaski vocabulary and grammar should clarify the implications of these findings and determine more closely Burushaski's affiliation within Indo-European.