This paper presents the qenerative analysis of longrnvowels in Oromo . mhe paper has four parts.rnThe fisst part presents a brief accounL of relatedrnliterature . All the r e vielqed literature has presentee. the lonerrnvowels in Oromo but they do not account for them by providingrnenough lin9uistic data. In ac1c'ition, all the r e viewed literatueerndoes not identify the surface l~nq vowels f rom the sase longrnvoqels.rnThe second part has treated the long vO>lels in Orom6.rnThe long vowels are found to be both distinctive and nondistinctive.rnThe distinctive lonq vOl-leIs occur followed byrnsingle consonant Â·. . They are also ide ntical in qualityrnto that of their short counte r parts. The non-distinctive lonqrnvowels again do not have an identical short c ounterrnpart s as the distinctive long vowel s. At the root l evelrnthey occur in the (I) , __ c 2 ,e nvironrnent . The predictabilityrnof the se long vowels (4.e non- (l.istinctive long vowels thatrncan appear in the (c l ) __ c 2 e nvironroent) is proved withrnfive evidence. The e vidence which his p roven the occurencernof the non-distinctive lonq vowels in the (c l )_ c 2 e nvironmentrnis (1) loans from A'Jlharic, (2) the Dird Talk in Oromo,rn(3) the ~lritten source , (4) the verb inflection especiallyrnthe glide ending roots ann (5) the metrical analysis ofrnpoetic stresÂ§ and compensatory l e ng thening.