This study addresses the phonological, morphological and semantic adaptation of borrowed Kiswahili nouns into Kisukuma. It aims at examining borrowed Kiswahili nouns into Kisukuma. It also seeks to identify and discover the phonological, morphological and semantic strategies that are involved in the adaptation of borrowed Kiswahili nouns into Kisukuma, and lastly, it assesses the impacts of borrowed Kiswahili nouns into the Kisukuma lexicon. Two approaches were used. These are Assimilation Theory and The Constraints and Repair Strategy theory. According to these theories, any borrowed word must conform into the recipient language by being assimilated into the system of the host language. Data collection was done using interviews, questionnaire, focus group discussion, observation and introspection methods. The findings show that the Kisukuma lexicon has been heavily influenced by Kiswahili. There are much more Kiswahili vocabularies in the lexicon of Kisukuma in different fields like education, agriculture, science and technology, sports, law, politics, among others. Moreover, the findings show that when borrowed Kiswahili nouns are adapted into Kisukuma, they are modified so as to conform into the Kisukuma system. This is done through several different phonological and morphological strategies that are used in the adaptation process. Semantically, some of the borrowed Kiswahili nouns are changed when they are adapted into Kisukuma. Some of the meanings of Kiswahili nouns are broadened, others are narrowed while other meanings incur a total meaning shift. Furthermore, the findings reveal that many Kisukuma speakers, especially the young generation and the elite ones, are using Kiswahili words in their conversation. As a result, most of the Kisukuma vocabularies are replaced by those of Kiswahili. Since this study focused only on one aspect, that is , only nouns, it is recommended that there is a need to conduct a study to investigate on the other aspects such as tense and aspect, adjective, inflectional morphology, derivational morphology among others because these are the issues not covered in Kisukuma, especially in Jidakama dialect.