In this study we have measured the effect of light intensity levels on the systolic and diastolic blood pressure, blood oxygen saturation, heart pulse rate and tympanic temperature of the employees of three pharmaceutical companies in Ramallah andAl-Bireh district. The employees were chosen to represent the population of the study. The companieswere: Birzeit pharmaceutical company-Ramallah branch (BZPR), DarAlshifa pharmaceutical company (DA), and Birzeit pharmaceutical company-Birzeit branch (BZPB). The sample of the study consisted of 219 employees distributed over the three companies. The parameters were measured before and after the employees work day. The results showed that there is a relation between light intensity levels and all the health parameters. The results of measurements of systolic and diastolic blood pressure show that they are increasing with increasing light intensity levels. The values of Sig P-values were found to be 0.000 and 0.023 for systolic and diastolic blood pressure respectively, while the results of SPO2% show that they decrease with increasing light intensity levels, with Sig P-value was calculated to be 0.000. The tympanic temperature increases when light intensity level increases, (Sig P-value = 0.002). However all changes were in normal range of the recommended standards.