Information and communication technology (ICT) has infiltrated society to the point of becoming essential to much of its everyday functioning. People rely on ICT to communicate, access information, and stay connected in an increasing globalised community. In many developed countries, ICT is now strongly featured in education for teaching and learning. In South Africa, as in other developing or partly developed countries, ICT use in education remains limited. This research was conducted to explore and understand how those South African science teachers who have access to ICT use it when they teach science. It was done to explain some of the reasons those teachers use ICT in the ways that they do, and to gain a better insight into the value that using ICT adds to both teaching and learning science. The research was designed as a mixed methods study, using both quantitative data collected from 267 Grade 8 science teachers in South Africa through the SITES 2006 teacher questionnaire, and qualitative data collected from three science teachers, all of whom taught science in a context of limited resources typical of a developing country. The data collected and analysed in this study showed that when science teachers have access to ICT for teaching and learning in classrooms typical of developing country contexts, they are able to use that ICT effectively to add value to teaching and learning. The greatest value is added when the teacher has a high technological pedagogical content knowledge. Secondly, at the level of the teacher, personal entrepreneurship is a key factor in a teacher’s ability to use ICT to add value to teaching and learning and to support the educational objectives based on 21st century learning objectives. Thirdly, teachers use the available ICT resources in a variety of ways but it seems that access to a personal computer, either laptop or desktop, in the classroom is a minimum requirement for ICT use in subject teaching. And lastly, the gap between ICT policy intentions as outlined in the South African e-Education White Paper (DoE, 2004b) and ICT practice remains large. There was no evidence from this study to suggest that the ICT policy intentions influenced practice at classroom level.