Potential application of a simple panel solar cooker design (Cookit) to inactivate bacteria in drinking water was investigated. Escherichia coli (E. coli) was used as an indicator species in this study. Bacterial contaminated water was collected from Mzimnene R iver in Manzini region of Sw aziland. Water samples were put in Cookits and exposed to solar radiation for different time intervals (0, 30, 60, 90, 120, 150 and 180 min). Changes in water temperature were monitored and E. coli counts (cfu/ml) were enumerated for each sample. The standard solid plating procedure for enumerating bacteria was used. The results showed rapid decline in E. coli count when water temperature reached about 55ºC and this was attained within 2 h of exposure to solar radiation. The findings suggest that there is potential in using the Cookit to inactivate bacteria in drinking water. It is recommended that further investigations be conducted at a larger scale, over longer periods and under different weather and climatic conditions. The effectiveness of the Cookit should also be further evaluated with more resistant waterborne bacteria, bacterial spores, protozoan cysts, and viruses.