This study investigated the phonological processes affecting Ndamba vowels. The study aimed at discovering different phonological processes that are applied in the Ndamba but affect vowels only. The objectives of the study were; i) To identify consonants and vowels in Ndamba ii) To identify morpheme structure conditions of the Ndamba words iii) To describe the phonological processes that affects vowels in Ndamba through using rules. The study was guided by the Generative Phonology theory that was propounded by Chomsky and Halle (1968). The study employed a qualitative research approach in which documentary review, Structured Interview and Introspective were used to collect data. A list of 300 words was used to collect the required data for analysis in this study. Out of 300 words only 124 words were purposefully used as examples in the analysis while the remained words have no phonological changes. The findings of the study indicates that the Phonological Processes that Affects Vowels in Ndamba are in two category which are Assimilatory Processes which includes Vowels Lengthening which includes Compensatory vowel lengthening and Penultment vowel lengthening, High Vowel Deletion, Nasalization, Glide formation, and Non Assimilatory Processes which includes: Prothesis, Syncope and Apocope. The rules ordering in all these processes are formulated with comments for elaboration. Moreover the study also shows phonological processes, in particular vowel lengthening, vowel deletion and epenthesis do take place in order to conform to the phonetic and the sequential Morpheme Structural Consonants system MSC(s) of Ndamba, while glide formation takes place in order to conform to the phonotactics conditions of the language. Furthermore, it has seen that most of the rules are crucially ordered. The study concludes that the phonological processes do resemble on Bantu languages however there are peculiar cases. The study recommends that some further research to be carried out on phonological processes affecting Ndamba sounds particularly on supra segmental features.