This study aims to examine the effect of effectiveness of work culture and internal motivation in improving public services and its implications for the performance of civil servants (ASN) and the performance of the Aceh Selatan Health Office. The intended population was 123 people, and sample members were determined using a census technique where the entire population members were as a sample. Data were analyzed with the Structural Equation Modeling (SEM) thru AMOS software. The result proves that Work Culture affects Public Service, Internal Motivation affects Public Service, Work Culture affects ASN performance, Internal Motivation affects ASN performance, Work Culture doesn’t affect Aceh Selatan Health Office Performance, Internal Motivation affects Aceh Selatan Health Office Performance, Public Service affects ASN performance, Public Service affects Aceh Selatan Health Office Performance, Public Service fully mediates the Work Culture effect on ASN performance, Public Service partially mediates the Internal Motivation effect on ASN Performance, Public Service fully mediates the Work Culture effect on Aceh Selatan Health Office Performance, and Public Service partially mediates the Internal Motivation effect on Aceh Selatan Health Office Performance. It appears that there is one relationship that does not occur, namely work culture cannot affect Aceh Selatan Health Office Performance. However, although it does not directly affect significantly, work culture can have a role on Aceh Selatan Health Office Performance through public service, thus explaining that public service in the work culture model affects Aceh Selatan Health Office Performance in this research model to function as a full mediator. In addition, public service has also been shown to function as a partial mediator in the model of internal motivation affecting Aceh Selatan Health Office Performance. So the model for improving the performance of the Aceh Selatan Health Office institution is a function of strengthening work culture, increasing internal motivation, increasing public service and also increasing ASN performance.