Poland
According to the available materials, the main region for traditional polyphony is the Podhale region in the Tarra Mountains, southern Poland. Two-part polyphony with parallel thirds, and more interestingly, fifths, with the elements of Lydian scale has been documented here:
Survival of the tradition of polyphonic singing in the mountains is also evident according to Dahlig: “Only in the Carpathian area is polyphonic singing found. There, one singer initiates a song and after a few notes others join in: some take the main melody while the rest add a voice below” (Dahlig, 2000:703). According to this description this polyphonic style has elements of two-part heterophonic polyphony, with groups singing both parts and the number of parts changing from two to three. Some influence of European professional music is also evident in parallel thirds and specific “leading” seventh step (giving the music the feel of a European Dominant chord).

Slovakia
According to available data, the tradition of more contemporary polyphony is spread quite widely throughout the territory of Slovakia. It is mostly two-part singing in parallel thirds (mostly in Northwestern Slovakia). In the northern part fifths have a greater importance, and in the western part – thirds and sixths (Elschekova, 1963, 1981). Both parts are usually performed by groups of singers. At the very beginning of the songs (as in virtually all polyphonic cultures), the individual performer starts singing, joined later by others. In some cases the group starts together in unison, which is possibly a later tradition, as with folk music it is very unusual to coordinate the pitch and rhythm of the songs beforehand and to prepare for the beginning. Musical phrases usually finish on one note, in unison. As both parts are performed by groups of singers, the heterophonic division of parts is possible. In such cases a few three- or four-part chords appear in the musical texture. Perhaps the most developed form of heterophonic polyphony has been recorded in the mountainous central part of Slovakia:
And finally, in a few villages of the Northwestern part of Slovakia a tradition of drone polyphony with secondal dissonances and small-range melodies has been documented. The drone is rhythmic (it moves a major second up and down).

Czech 
Part-singing is quite usual for this Slavic country, although the eastern part of the Czech republic (Moravia) is more polyphonic than the western part (Bohemia).
The polyphonic traditions of Moravia are connected to the late influence of European melodies and harmonies. As in most European polyphonic traditions of later origin, leading of the main melody in parallel thirds (and sixths) is dominating. Both parts can be performed by groups of people primarily in parallel thirds and sixths, usually in two parts, but sometimes in three.
According to Zelinska and O’Connor, one of the most developed traditions of part singing exists in Chodsko. Besides two parts singing in parallel thirds and sixths, two other parts also hold the double drone, apparently imitating the pedal sound of the bagpipe:
In some two-part songs in Chodsko the melodic lines are so intertwined that it is difficult to tell which part leads the main melody (Zelinska, O’Connor, 2000:719-720).