Dissertation (MSc Nursing Education)Web-based learning can provide nurses with the opportunity to develop new knowledge and skills for the management and prevention of diseases including the emergence outbreak. However, concerning the covid-19 outbreak in Zanzibar studies shows that only a traditional method of face to face was employed to train nurses which resulted in a very low number of nurses who received proper training on prevention and management of covid-19. Thus the study aimed to design and tests the effect of web-based training system on knowledge and skills for pandemic preparedness and responses among frontline nurses from Zanzibar. A single group quasi-experimental study was conducted on a set of 139 nurses from Zanzibar. A web-based training system was developed by the researcher followed by Leightons 7 stages of system development. Learning content was adapted and modified from CDC, WHO and MoHCDGEC Tanzania and were organized into five modules. The total learning time per lesson was 90 minutes. To test the effect of the developed tool a pretest-posttest design was adopted. Frontline nurses were recruited from different health facilities in Zanzibar and devotedly involve in training for two weeks. A computer-generated questionnaire with a total of 60 items was used to measure the knowledge and cognitive skills of the respondents and evaluate the level of the developed system satisfaction. Data were analyzed using SPSS software. Findings from the study indicates a significant change in the knowledge scores followed by web-based intervention with a mean difference of 3.58 (P < 0.001) and cognitive skills scores, mean difference of 3.07 (P < 0.001). Those who scored low in the baseline test were found to significantly contributed much in the change of knowledge and skill in posttest (β = -0.66 and P <0.001) for knowledge and (β= -0.62, and P<0.001) for cognitive skills. The range of system rating by users was varied across quality and usability variables from (M = 2.50, SD = 1.265) to (M = 4.04, SD = 1.188) indicating the level of satisfaction toward the developed web-based system. The developed web-based system was successful improved nurses’ knowledge and skills for pandemic preparedness and response. Nurses positively evaluated the system in terms of quality and usability.