Among students of public health, there is a wide variation of aptitude, preparation, and motivation for the study of biometry. Self-paced instruction offers a way to deal with problems arising from such diversity. The Proctorial System of Instruction (PSI) as described by Keller was used to present two elementary biometry courses. Although there were some difficulties in preparation and administration of the courses, students and instructors agreed that the method is an acceptable alternative to the more usual lecture method. The diversity of student backgrounds is noted and a PSI flow chart is included. (Author/LBH)