The UK educational system is currently under pressure from many quarters to increase its use of educational technology. Within this context, this thesis investigates the nature of a range of factors which influence teachers' use of computer assisted learning (CAL), focusing on biology teachers in Further Education (FE). The factors were identified from the literature, and include aspects such as resourcing, and the teachers' classroom practice and educational philosophies. There were three main stages to the thesis research. The first stage involved a survey of 68 FE biology teachers. The second stage involved two interviews each with 20 of the survey respondents, producing approximately 80 hours of audiotape. The third stage involved a total of nine classroom observations with six of the interviewees, producing approximately nine hours of videotape and nine hours of audiotape. The conclusions describe how the factors interacted to affect CAL use amongst the FE biology teachers. The findings stress the importance of teachers' development of classroom familiarity with computers; this development was encouraged by both current and previous exposure to the classroom practice of other computer-using teachers. The teachers involved in the study were generally positive about educational technology, but critical about many currently available biology programs; this critical perspective was particularly evident amongst the more student-centred teachers. The findings outline a list of criteria that the teachers appeared to consider when reviewing programs, and describe the relationship between the use of software and the teachers' classroom practice. The conclusions outline the potential of a framework developed by Brown and McIntyre (1993) for future studies of how classroom practice affects, and is affected by, educational technology. The conclusions also make recommendations, based on the findings, to those responsible for FE policy and staff development about how they might help to increase teachers' use of CAL.