Conducted in urban and rural schools in two provinces of South Africa, the present study reports biology learners' understanding of concepts about genetics and inheritance. Participants were Grade 11 and 12 learners, aged 15-16 years. The tools included a written questionnaire, interviews, pre- and post-paper and pencil tests and focus group discussions. A pilot study, aimed at identifying participants' views and ideas as well as checking the suitability of the study instrument, was also conducted. Findings from the pilot study and the input of experienced researchers were used to modify the tools, to include multiple-choice questions and address issues relating to validity and reliability. Preliminary findings of this ongoing project indicated a lack of understanding of the mechanisms and processes involved in genetics and inheritance by participants. The results demonstrated misconceptions on the nature of genetic information in cells. Prominent also, was a conflict between traditional beliefs and scientific views on inheritance. Teachers and learners reported the teaching and learning of genetics to be difficult, a finding consistent with studies investigating similar constructs. (Contains 4 tables.)