Four natural asphalts (NAs) from Buton Rock, Indonesia, which were abbreviated as BRA-A, BRA-B, BRA-C and BAR-D, were continuously extracted by solvents, subdivided into four fractions and analyzed with Fourier transform infrared (FTIR) spectrometry. The transmission and reﬂection FTIR techniques were used to distinguish among different samples and fractions and to examine information concerning their structure, composition and structural changes upon fractional extract. Upon FTIR analysis, the methyl, methylene, oxhydryl and carboxyl groups are the major composition of these NAs. Some strong bonds at the zones of 2922-2856 cm-1, 1707-1606 cm-1 , 1453-1373 cm-1 , 1030 cm-1 and 872-748 cm-1 are assigned to >CH2 & -CH3 & –OH in carboxlic acid, ester & benzene ring, >C=O & -C-CH3, –CH2OH, -(CH2)n- & substituted benzene, etc. Much more care should be taken to investigate both N-containing functional groups and mineral multiphase compositions probably present in BRA-B, C and D.