From the 19th century folk music began to be exploited as a means of promoting national and political ideas, initiating thus the concept of rooting national music in folkloric elements. In the second half of the century this idea was brought to fruition primarily by using popular tunes created during the period of National Revival in urban environments and through the activities of choirs and tambouritza groups which were being established as the first amateur music societies. In the 20th century, particularly in the period between the two world wars, national music drew on the traditional music of Croatian peasantry, recognised as the autochthonous feature of Croatian culture.
At that time, a new context for performing folk art was established within the framework of the national cultural programme implemented by the Peasant Unity (a cultural organisation of the Croatian Peasants' Party), i.e., folklore festivals, where the peasants themselves performed songs and dances in their unaltered ("authentic") form. Folk art affirmed in this way was raised to the utmost value of national culture, while the amateur fostering of local heritage and its performance at folklore festivals have remained to this day the dominant forms of the public performance of folk music in Croatia. The best folk festivals in Croatia today include: The International Folklore Festival (Zagreb), Vinkovci Autumn, Đakovo Embroidery, Brod kolo, Festival of Istrian Folk Music and Dance and Festival of Dalmatian Folklore.
From the year 1950 on, folk ensembles established in urban environments also began performing folk dances and songs in more or less arranged forms (the only professional one being the Folk Dance and Song Ensemble "Lado" - Zagreb). There are only a few festivals devoted exclusively to traditional music (and not to dance), e.g. the Dalmatian Klapa Festival - Omiš; the festival Songs of Međimurje - Nedelišće), while traces of folk music are also recognisable in the music written for popular music festivals: Melodies of Istria and Kvarner; Kajkavian Songs - Krapina; Slavonija - Požega). From the 1980s, elements of folk music began appearing in various arrangements, compositions and interpretations of jazz, rock and other musical genres, gaining even greater momentum in the 1990s, as a reflection of the so called world music.
The differing histories and cultural heritage of the Croatian regions where Central-European, Mediterranean and Balkan cultures met, along with inter-regional influences and exchanges, created an extraordinarily diverse traditional music repertoire as well as a variety of performing styles and folk instruments. Accordingly, only by giving a brief outline of the characteristic features of specific musical and folkloric regions it is possible to give a broader picture of this type of music.
In Slavonija and Baranja diatonic two-part singing with endings that were either unison (older tradition) or in a perfect fifth (newer tradition also known as na bas singing) prevails, while the traditional urban songs reflect the influence of 19th century Central-European popular music that is simple in form and has major mode (rarely minor mode) features. The bagpipe (gajde) is the traditional instrument accompanying the dances. In the 20th century they were suppressed by the tambura (a long-necked lute) introduced into the Balkans in the 14th and 15th centuries by the Turks and brought into Slavonija during the movement of the Bunjevci and Šokci where it gradually became the local folk instrument. From the 19th century promoted as the national instrument, it became embedded in all regions of Croatia.
Specific of Međimurje are one-part tunes (popevke) with melodic lines of greater range, based on old church modes (particularly Doric and Aeolic) and pentatonic scales. The characteristic quintic transposition of melodic parts is of Hungarian influence. Some of the newer songs are in major mode. Traditional instruments include the drone zither (trontole) and dulcimer (cimbal), frequently together with fiddle instruments (goslari) making mixed groups. After the incorporation of Međimurje into Croatia (1918) they were substituted by tambouritza players and brass bands (bandisti).
In the regions of Central Croatia there are various types of diatonic two-part singing. Along with bagpipes (dude) which were used until the beginning of the 20th century in regions of Podravina, Bilogora and Moslavina, wind instruments, such as flutes (žvegla, fajfa, and dvojnice) were also frequently played. From the end of the 19th century fiddle ensembles (guci, muzikaši), in the northern regions of Croatia joined by the dulcimer, were the most frequent instrumental groups, while in the 20th century these groups were supplemented by tambouritzas and chromatic accordion or else completely substituted by tambouritza players.
In view of the fact that Lika and Gorski kotar connect continental and coastal Croatia, they are regions of intensive inter-permeation of Adriatic, Dinaric, and Alpine and Panonian traditional cultures which at times blend into specific forms. The most prominent example is the rozgalica from Lika, a combination of the Dinaric ojkanje singing and the Panonian na bas singing. In Gorski kotar alpine influences (accordion, major mode) dominate.
The older musical tradition of Istria and the Kvarner region includes three styles of two-part singing, among which the one in the so called Istrian scale is particularly prominent due to its non-tempered tonal row with the movement of the voices in parallel, somewhat narrower minor thirds with unison endings, and with the frequent insertion of neutral meaningless syllables (tarankanje). The other two-part style, ćićarijsko bugarenje, is characterised by even narrower intervals, and a two-part singing of discant type, with combined elements of drone accompaniment and contrary motion between the parts, is characteristic of the Italian population. Old traditional instruments include the sopele (roženice), the surviving form of the older European shawm (a woodwind instrument of oboe type), and meh and šurle (both woodwind instruments of clarinet type). The newer tradition which is evidently under the influence of the neighbouring Alpine regions, is characterised by tonal music and fiddle ensembles associated with diatonic accordion and/or clarinet (gunjci).
The older Dalmatian tradition is characterised by non-tempered chromatic and/or narrow range diatonic tunes (hinterland of central Dalmatia, northern Dalmatia, and the islands). One-part singing (monophonic) is characteristic of southern Dalmatia. Short vocal forms with ojkanje, a distinctive way of singing melodic ornaments on the syllable "oj", with vigorous shaking of the voice, is considered an old Balkan tradition. Longer narrative songs are performed by soloists, frequently to the accompaniment of gusle (a one-string fiddle), widely spread throughout the Balkans, and registered in Croatia at the beginning of the 16th century. Confirmations of the diple (mišnjice, mih), a rare type of eastern Mediterranean bagpipe instrument, an early form of such instruments in Europe, dated here from approximately the same period. In the 19th century in some parts of Dalmatia they were substituted by the lijerica (a three-strings fiddle), which spread from Greece throughout the Adriatic coast at the beginning of the 18th century and which has remained in practice to the present day only in southern Dalmatia. Later traditional music is in major mode with Mediterranean and Central-European features. During the second half of the 19th century, under the influence of musical activities in National Revival period, multi-part singing of chordal (harmonic) structure in major mode developed and was performed by smaller groups of male singers (klapa singers). In the 20th century klapa singing, as a form of musical amateurism, became the dominant musical expression of the Dalmatian region. The mandolins, instruments of Italian origin, are part of this tradition.