Concern has been expressed in recent years about the accuracy of medication administered by nurses in Papua New Guinean hospitals. Attention has been focused on the calculation of the drug dosages. This paper discusses the processes involved in the administration of medication, and reports on a study to evaluate the competence of student nurses at both theoretical and practical aspects of drug administration. The study aimed: to examine the abilities of student nurses on calculating drug dosages by a paper/pencil test; to examine the abilities of student nurses in the practical administration of drug dosages; to determine the extent of the relationship between the two tests; and to investigate the extent and type of student errors in the tests. Results indicate that these students are experiencing little difficulty with the calculation of the dosages on paper, but there are additional errors apparent in practice. Therefore, it is argued that drug administration must be seen as an entire process, and should be taught and tested as such. This supports the argument that vocational mathematical skills must be taught in the context in which they are used if the students are to be able to apply their skills successfully in the real situation. (Author/JN)