Coronavirus disease (COVID-19) greatly affected medical personnel. Researchers have documented the detrimental effects of COVID-19 on the health of medical personnel, among them being high levels of infection and mortality, significant financial strains, anxiety related to both known and unknown information, and fear of ongoing impact and uncertainty. The objective of the study was to investigate the effect of COVID-19 on the psychological health of medical personnel. The study adopted a cross-sectional descriptive research design and was anchored on the Stress and Coping Theory. They targeted all 18 hospitals in Eldoret, comprising 3 public and 15 private hospitals. The population included 34 doctors, 55 laboratory technicians, 71 clinical officers, and 219 nurses, totalling 379 as a population under study. A sample size representing 50% of the total population was selected for the study. In a proportionate way, doctors, laboratory technicians, clinical officers, and nurses were selected at a ratio of 1:2:3:4, respectively. The snowball sampling technique was used to select respondents. The data was gathered through a questionnaire. The study's findings were analysed quantitatively. Multiple linear regressions were applied to examine the effect of COVID-19 on the health of medical personnel. Findings indicated that the psychological effect of COVID-19 had a positive and significant influence on the health of medical personnel (β1 =.646, P< 0.05). Highlighting the profound psychological effects, the majority (77.7%) experienced stress. Therefore, COVID-19 had profound psychological effects on the health of medical personnel in hospitals in Eldoret town. There is a need to implement and expand psychological support programs tailored to the needs of medical personnel. Providing access to counselling services, stress management workshops, and peer support groups could help address the psychological challenges faced by medical personnel in responding to crises such as the pandemic.