Background: Most studies in advanced care settings reported that the increasing workload increases the work-life imbalance and harms the mental health of health workers. The COVID-19 pandemic's tracing, testing, treatment, and mass vaccination also have multiplied the primary healthcare workers' workload. Nevertheless, studies on primary care workers are scarce. This study aimed to investigate how the COVID-19-related work-life balance impact stress on primary healthcare workers in the third years of the pandemic. Methods: The study was a cross-sectional, web-based survey conducted on primary healthcare workers in Kediri Regency, Indonesia, with the highest Omicron case surge worldwide. It was conducted right after the surge between July and August 2022, the third year of the COVID-19 pandemic hit Indonesia. Under coordination with the local government health officials, primary healthcare workers were invited to participate in an online survey. The respondents were asked to evaluate their socioeconomic demography, work conditions, personal life, and perceived stress (using the Perceived Stress Scale by Cohen et al.) during the pandemic. Their work-life balance was evaluated using the Work/Nonwork Interference and Enhancement Scale. We used several hierarchical linear regression models to determine what variables contribute to working stress among primary healthcare workers. Results: Socioeconomic demography variables, including gender, age, marital status, years of professional experience, and educational level, were not significantly associated with stress levels among our respondents. Separately, work conditions and personal life variables did not associate with stress levels. However, work-life balance dimensions as a predictor of primary health workers' stress were significantly associated with primary health workers' stress. Conclusion: The work and personal lives interferences related to COVID-19 handling created a work-life imbalance, increasing the propensity for higher stress among primary health workers. At the same time, enhancement between work and personal lives decreased the stress level. Social support from the work environment and family protects health workers against stress during the pandemic.