This study aims to determine the effect of service quality, brand image and promotion of purchasing decisions at MCU Eka Hospital. The research design used was quantitative and descriptive. The study population included 396 service users of MCU Eka Hospital. The sample size is 76 respondents by using purposive sample method. The research data was collected by distributing questionnaires to obtain the required data. Data testing techniques include instrument test and classical assumption test. Methods of data analysis used are multiple linear regression analysis method, t test, f test, coefficient of determination test (R2) and inter-dimensional correlation analysis with the help of SPSS 23.0 for windows program. The results showed that the quality of service, brand image and promotion have a significant positive effect simultaneously to the purchase decision at MCU Eka Hospital. Partially the quality of service has a significant positive effect on purchasing decision, brand image has a significant positive effect on purchasing decision and promotion have a significant positive effect on purchasing decision. Further research is suggested to add other variables that influence purchasing decisions that have not been used in this study such as price, product and customer relationship management.