Saudi Arabia's fast-growing pharmaceutical market aims to retain employees to increase organizational effectiveness and reduce attrition costs. This study aimed to investigate employee retention determinants in Saudi pharmaceutical companies. In total, 325 responses were collected and analysed. Quantitative research was conducted using an electronic survey sent to Saudi pharmaceutical employees through different social media platforms. Different variables were collected from the survey tool using several question formats. Descriptive and inferential statistics were used for data analysis. Six determinants were identified to have a positive correlation with employee retention: salary/benefits, job/work conditions, work relationships, company culture, motivation, and leadership within the company. The motivation was a key factor influencing employee retention. Nearly 52.1% to 91.1% of employee retention was explained by the aforementioned determinants. Job/work conditions and motivation in the company were significant positive predictors of employee retention. Our study showed a significant relationship between salary/employee benefits, motivation, work conditions, organizational culture, leadership support, and employee retention in pharmaceutical companies in Saudi Arabia. Leaders in Saudi pharmaceutical companies should maintain long-term staff retention to boost organizational performance and minimise the cost of employee attrition.