The new Science and Technology Curriculum Framework recently issued in Taiwan advocates the teaching of integrated science and technology with greater emphasis on basic skills. Science teachers are not used to teach in this way, they need different abilities and skills in order to do so. Using various effective professional development strategies, including a collaborative action research approach, the aim of this study was to help science teachers develop professionally through the development of instructional modules on integrated science and technology. A research team was formed consisting of science educators/researchers, graduate assistants and science teachers from six junior high schools in the central area of Taiwan. In order to involve teachers collaboratively over an extended period of time, the entire study went through preparatory, elaborative and disseminative stages for three consecutive years. Various professional development opportunities were built-in. The instructional modules developed were discussed by participants of this study and evaluated by external experts before they were tried out in actual classroom settings. Both qualitative and quantitative methods, including field notes, interviews, observations, video-taping, audio-taping, document analysis, and surveys of students' and teachers' opinions were used to collect data for a closer examination of the effectiveness of the instructional modules and of the increase in teachers' instructional proficiencies. Overall, teachers' interdisciplinary experiences and knowledge increased. They were more flexible and resourceful in using instructional strategies that best fit the instructional settings. Their knowledge and skills in using information and communication technologies in science classrooms also increased considerably.