The aims of this research are: (1) to develope instructional multimedia for Science instruction for the grade six students of elementary schools; (2) to investigate aspects the quality of the developed instructional basic website ‘cyeber’ for Science instruction.The respondents of the try-out in this research consisted of one media expert, one subject matter expert, three students for One-To-One try-out, 12 students for the Small-Group Try-Out, and 30 students for the Field Try-Out. The data collected in this research included the evaluation data from the subject matterexpert, the evaluation data from the media expert, and data from the students on the aspects of content, instruction, and media. The data were collected using an evaluation sheet, questionnaire, Pretest and Postest to reveal the effectiveness of the product implementation. The data were analyzed using the statistic descriptive technique. The findings suggest that: (1) the product of the development of the instructional basic website ‘Cyeber’ for Science instruction in the grade six of elementary schools is interactif; (2) the model was developed through steps consisting of analysis, design, production, and evaluation stages; (3) viewed fromthe content, instruction, and media aspects the quality of the developed instructional basic website ‘Cyeber’ was very good with average score of 4.40 for the content, 4.39 for the instruction aspect, and 4.48 for the media aspect. The effeciveness of the developed instruction multimedia was indicated by difference in the students’ average scores in the pretest (M=45.30) and the postest (M=73.19). The percentage of students who master the learning material after using the developed instructional multimedia was 85.11%