This study aimed at Analysis of Lexicon Expansion Strategies in Chasu Metaphors. The study was guided by Cognitive Metaphor Theory (CMT) by Lakoff and Johnson (1980).The objectives of this study were to examine colours, body parts, and physical objects metaphors as lexicon expansion strategies in Chasu. The data collection methods which were used in this study are questionnaire, focus group discussion and introspection where the analysis was largely qualitatively in nature. Based on the reviewed literatures, the inspiration behind this study rests on the fact that the researcher assembled all metaphors found in Kindungu dialect of Same District but decided to examine only colours, body parts and physical objects metaphors as they are mostly used in Chasu day to day life. The study is significance to the field of Morphology because new vocabulary has been created due to the mapping of two domains of source and target. The study shows that colour, body parts, and physical object metaphors do not only elaborate meaning of the abstract entities, but also cover the physical and abstract concepts which are absent in the literal expression in Chasu. The concepts that are covered by these chosen metaphors in Chasu are meanings based on Life Phenomena such as Colour metaphors as in mwaka wa mani ‘a green year’ to mean a year of success in harvest, enough rainfall; Body parts metaphors as in echumia itumbo ‘to produce for stomach’ that is, produce for food; or Physical objects metaphors as in eikaa he nyumba ya ibati‘he lives in the house roofed by iron sheets’ to mean he has wealth. Other concepts covered generally including expressions of human behaviours, person social roles, borrowed concepts from other languages, leadership, education, physical appearances, beliefs, physical distance, race, weather, natural calamities and technical inventions. The study recommended that there is a need for semantic analysis of dead metaphor in these metaphors, also more colour needs to be examined apart from that discussed, and the need for comprehensive studies based on the analysis of metonymy of these metaphors for lexicon expansion in other Bantu languages.