The teaching potential of videocassettes and videodiscs are reviewed, together with an indication of when mass access is likely to rival that of broadcast television. It is argued that videocassettes and videodiscs, with their focus on small groups of viewers and interaction, have far ranging consequences for instructional television design, and that the challenge to broadcast television from new television technologies lies in the control learners can exert over their viewing of the television material. Since the immediate challenge is presented by videocassettes, the implications that the characteristics of this technology have for television design are explored. The changes to broadcast educational television that are likely to result from the impact of the videocassette medium within the next decade are explored by means of a brief scenario. (Author/DB)