All of the tenth grade pupils in schools in Greenland participated in an investigation about the sexual behaviour of young Greenlanders and their knowledge about AIDS. This formed part of monitoring of the stop-AIDS campaign in Greenland. The investigation was carried out by distribution of anonymous questionnaires in the schools on 17.10.1988-21.10.1988. All of the pupils present (440 out of 539) participated. The investigation revealed that nearly all had heard about AIDS. Many know how the infection is spread and how the infection can be prevented. A great deal of information is still required and, perhaps to a great extent, information in the Greenlandic language. Greenlandic girls are somewhat more sexually active than boys of the corresponding ages in the same class but, in general, the number of sexual partners is relatively high when this age group is considered. The investigation will be repeated in exactly the same way at a later date to provide insight about how behaviour and knowledge are altered in relation to the AIDS campaign.