Abstract While scholars in the sociolinguistics of aging have shown that communication in eldercare is characterized by the predominance of infantilizing speech or elderspeak, sajiao, a self-infantilizing speech, has not been examined in this context. Further, current research on sajiao has focused primarily on young women. How sajiao is used in intergenerational communication involving adults and older adults is rarely examined. Drawing on two years of ethnography in two adult day centers in Taiwan, this paper examines the negotiation of power and solidarity through sajiao in dementia care. Sajiao is used for both task-oriented/transactional goals and interpersonal/relational goals and often serves multifunctional purposes to influence and to connect simultaneously. The intent and effect of sajiao as strategies of persuasion and influence (that is, power) and/or strategies of engagement and connection (that is, solidarity) is jointly constructed and negotiated. The multiple data sources of this longitudinal study—including ethnographic observations, interviews, and video-recordings—allow for richly contextualized interpretations of interactional episodes and reflective accounts, revealing a complex picture of power and solidarity negotiated through sajiao. This study contributes to research on eldercare communication by demonstrating the ambiguity and polysemy of discursive strategies in eldercare communication with regard to power and solidarity.